Category: WORKOUT

Everything is connected. You’ve probably heard that before, but it bears repeating. Below are five ways to boost both your individual health and the health of our planet — a combination that environmentalists call co-benefits.

How your health and planetary health intersect

Back in 1970, Earth Day was founded as a day of awareness about environmental issues. Never has awareness of our environment seemed more important than now. The impacts of climate change on Earth — fires, storms, floods, droughts, heat waves, rising sea levels, species extinction, and more — directly or indirectly threaten our well-being, especially for those most vulnerable. For example, air pollution from fossil fuels and fires contributes to lung problems and hospitalizations. Geographic and seasonal boundaries for ticks and mosquitoes, which are carriers of infectious diseases, expand as regions warm.

The concept of planetary health acknowledges that the ecosystem and our health are inextricably intertwined. Actions and events have complex downstream effects: some are expected, others are surprising, and many are likely unrecognized. While individual efforts may seem small, collectively they can move the needle — even ever so slightly — in the right direction.

Five ways to improve personal and planetary health

Adopt plant-forward eating.

This means increasing plant-based foods in your diet while minimizing meat. Making these types of choices lowers the risks of heart disease, stroke, obesity, high blood pressure, type 2 diabetes, and many cancers. Compared to meat-based meals, plant-based meals also have many beneficial effects for the planet. For example, for the same amount of protein, plant-based meals have a lower carbon footprint and use fewer natural resources like land and water.

Remember, not all plants are equal.

Plant foods also vary greatly, both in terms of their nutritional content and in their environmental impact. Learning to read labels can help you determine the nutritional value of foods. It’s a bit harder to learn about the environmental impact of specific foods, since there are regional factors. But to get a general sense, Our World in Data has a collection of eye-opening interactive graphs about various environmental impacts of different foods.

Favor active transportation.

Choose an alternative to driving such as walking, biking, or using public transportation when possible. Current health recommendations encourage adults to get 150 minutes each week of moderate-intensity physical activity, and two sessions of muscle strengthening activity. Regular physical activity improves mental health, bone health, and weight management. It also reduces risks of heart disease, some cancers, and falls in older adults. Fewer miles driven in gas-powered vehicles means cleaner air, decreased carbon emissions contributing to climate change, and less air pollution (known to cause asthma exacerbations and many other diseases).

Start where you are and work up to your level of discomfort.

Changes that work for one person may not work for another. Maybe you will pledge to eat one vegan meal each week, or maybe you will pledge to limit beef to once a week. Maybe you will try out taking the bus to work, or maybe you will bike to work when it’s not winter. Set goals for yourself that are achievable but are also a challenge.

Talk about it.

It might feel as though these actions are small, and it might feel daunting for any one individual trying to make a difference. Sharing your thoughts about what matters to you and about what you are doing might make you feel less isolated and help build community. Building community contributes to well-being and resilience.

Plus, if you share your pledges and aims with one person, and that person does the same, then your actions are amplified. Who knows, maybe one of those folks along the way might be the employee who decides what our children eat from school menus, or a city planner for pedestrian walkways and bike lanes!

About the Author

Wynne Armand, MD, Contributor

Dr. Wynne Armand is a physician at Massachusetts General Hospital (MGH), where she provides primary care; an assistant professor in medicine at Harvard Medical School; and associate director of the MGH Center for the Environment and … See Full Bio View all posts by Wynne Armand, MD

Dementia poses many challenges, both for people struggling with it and for those close to them. It can be hard to witness and cope with common behaviors that arise from illnesses like Alzheimer’s disease, vascular dementia, or frontotemporal dementia.

Caring for a person who has dementia may be frustrating, confusing, or upsetting at times. Understanding why certain behaviors occur and learning ways to handle a variety of situations can help smooth the path ahead.

What behaviors are common when a person has dementia?

People with dementia often exhibit a combination of unusual behaviors, such as:

• Making odd statements or using the wrong words for certain items.
• Not realizing they need to bathe or forgetting how to maintain good hygiene.
• Repeating themselves or asking the same question over and over.
• Misplacing objects or taking others’ belongings.
• Not recognizing you or remembering who they are.
• Being convinced that a deceased loved one is still alive.
• Hoarding objects, such as mail or even garbage.
• Exhibiting paranoid behavior.
• Becoming easily confused or agitated.
• Leaving the house without telling you, and getting lost.

Why do these behaviors occur?

Inside the brain of a loved one with dementia, picture a wildfire shifting course, damaging or destroying brain cells (neurons) and neural networks that regulate our behavior.

What drives this damage depends on the underlying cause, or causes, of dementia. For example, while the exact cause of Alzheimer’s disease is not known, it is strongly linked to proteins that are either gunking up or strangling brain cells. Someone with vascular dementia has experienced periodic insufficient blood flow to certain areas of the brain, causing neurons to die.

“As dementia progresses, the person loses brain cells associated with memory, planning, judgment, and controlling mood. You lose your filters,” says Dr. Stephanie Collier, a psychiatrist at Harvard-affiliated McLean Hospital.

Six strategies for coping with dementia-related behaviors

Dealing with distressing or puzzling dementia-related behavior can require the type of tack you’d take with a youngster. “Due to declines, older adults with dementia can seem like children. But people are generally more patient with children. You should consider using that approach with older adults,” suggests Lydia Cho, a McLean Hospital neuropsychologist.

• Don’t point out inaccurate or strange statements. “It can make people with dementia feel foolish or belittled. They may not remember details but hold onto those emotions, feel isolated, and withdraw. Instead, put them at ease. Just go with what they’re saying. Keep things light,” Cho says.
• Don’t try to reason with the person. Dementia has damaged your loved one’s comprehension. Attempting to reason might be frustrating for both of you.
• Use distraction. This helps when the person makes unreasonable requests or is moderately agitated. “Acknowledge what the person is saying, and change the activity. You could say, ‘I see that you’re upset. Let’s go over here for a minute.’ And then do an activity that engages the senses and relaxes them, such as sitting outside together, listening to music, folding socks, or eating a piece of fruit,” Dr. Collier says.
• Keep unsafe items out of sight. Put away or lock up belongings the loved one shouldn’t have — especially potentially dangerous items like car keys or cleaning fluids. Consider installing cabinet locks.
• Supervise hygiene routines. The person with dementia might need a reminder to bathe, or might need to have the day’s clothes laid out on the bed. Or you might need to assist with bathing, shaving, brushing teeth, or dressing.
• Spend time together. You don’t have to convince your loved one of your identity or engage in fascinating conversation. Just listen to music or do some simple activities together. It will help keep the person from withdrawing further.

Safety is essential when a person has dementia

Sometimes simple strategies aren’t enough when a loved one has dementia.

For example, if the person frequently tries to leave home, you might need to add child-proof covers to doorknobs, install additional door locks or a security system in your home, or get the person a GPS tracker bracelet.

If the person is frequently upset or even violent, you’ll need to call the doctor. It could be that a new medical problem (such as a urinary tract infection) is causing agitation. “If the agitated behavior isn’t due to a new health problem and is predictable and severe, we might prescribe a medication to help regulate mood, such as an antidepressant or an antipsychotic in cases of extreme agitation or hostility,” Dr. Collier says.

As dementia changes, seek the help and support you need

No one expects you to know how to interact with someone who has dementia. There’s a learning curve for all of us, and it continues even after you get a feel for the situation. “The process keeps changing,” Cho says. “What works today may not work next week or the week after that for your loved one. So keep trying different strategies.”

And get support for yourself, such as group therapy for caregivers and their families. You can also find information at the Alzheimer’s Association or Family Caregiver Alliance.

About the Author

Heidi Godman, Executive Editor, Harvard Health Letter

Heidi Godman is the executive editor of the Harvard Health Letter. Before coming to the Health Letter, she was an award-winning television news anchor and medical reporter for 25 years. Heidi was named a journalism fellow … See Full Bio View all posts by Heidi Godman

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Howard LeWine, M.D., is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

For people with obesity, weight-loss surgery can reverse or greatly improve many serious health issues, such as diabetes, high blood pressure, and pain. But these procedures also change how the body metabolizes alcohol, leaving people more likely to develop an alcohol use disorder. A new study finds that one type of surgery, gastric bypass, may increase the dangers of drinking much more than other weight-loss strategies.

“Alcohol-related problems after weight-loss surgery are a known risk. That’s one reason we require people to abstain from alcohol for at least six months — and preferably a full year — before any weight-loss surgery,” says Dr. Chika Anekwe, an obesity medicine specialist at the Harvard-affiliated Massachusetts General Hospital Weight Center. The new findings are interesting and make sense from a biological perspective, given the differences in the surgeries, she adds.

How does weight loss surgery affect alcohol absorption?

Weight-loss surgeries dramatically reduce the size of the stomach.

• For a sleeve gastrectomy, the most common procedure, the surgeon removes about 80% of the stomach, leaving a banana-shaped tube.
• For a gastric bypass, a surgeon converts the upper stomach into an egg-sized pouch. This procedure is called a bypass because most of the stomach, the valve that separates the stomach from the small intestine (the pylorus), and the first part of the small intestine are bypassed.

The lining of the stomach contains alcohol dehydrogenase, an enzyme that breaks down alcohol. After weight-loss surgery, people have less of this enzyme available. So drinking wine, beer, or liquor will expose them to a higher dose of unmetabolized alcohol. Some alcohol is absorbed directly from the stomach, but most moves into the small intestine before being absorbed into the bloodstream.

After a sleeve gastrectomy, the pyloric valve continues to slow down the passage of alcohol from the downsized stomach to the small intestine. But with a gastric bypass, the surgeon reroutes the small intestine and attaches it to the small stomach pouch, bypassing the pyloric valve entirely. As a result, drinking alcohol after a gastric bypass can lead to extra-high blood alcohol levels. That makes people feel intoxicated more quickly and may put them at a higher risk of alcohol use disorders, says Dr. Anekwe.

Findings from the study on weight loss surgery and alcohol

The study included nearly 7,700 people (mostly men) from 127 Veterans Health Administration centers who were treated for obesity between 2008 and 2021. About half received a sleeve gastrectomy. Nearly a quarter underwent gastric bypass. Another 18% were referred to MOVE!, a program that encourages increased physical activity and healthy eating.

After adjusting for participants’ body mass index and alcohol use, researchers found that participants who had gastric bypass were 98% more likely to be hospitalized for alcohol-related reasons than those who had sleeve gastrectomy, and 70% more likely than those who did the MOVE! program. The rate of alcohol-related hospitalizations did not differ between people who had sleeve gastrectomy and those who did the MOVE! program.

The health harms of alcohol use disorder

Alcohol use disorder can lead to numerous health problems. Some require hospitalization, including alcoholic gastritis, alcohol-related hepatitis, alcohol-induced pancreatitis, and alcoholic cardiomyopathy. As the study authors note, people who had gastric bypass surgery had a higher risk of being hospitalized for an alcohol use disorder, even though they drank the least amount of alcohol compared with the other study participants. This suggests that change in alcohol metabolism resulting from the surgery likely explains the findings.

Advice on alcohol if you’ve had weight-loss surgery or are considering it

“We recommend that people avoid alcohol completely after any type of weight-loss surgery,” says Dr. Anekwe. A year after the surgery, an occasional drink is acceptable, she adds, noting that most patients she sees don’t have a problem with this restriction.

People who undergo weight-loss surgeries have to be careful about everything they consume to ensure they get adequate amounts of important nutrients. Like sugary drinks, alcohol is devoid of nutrients — yet another reason to steer clear of it.

Gastric bypass has become less popular than sleeve gastrectomy over the past decade, mostly because it’s more invasive and slightly riskier. While the new study suggests yet another downside of gastric bypass, Dr. Anekwe says it can still be a viable option for people with severe obesity, as bypass leads to more weight loss and better control of blood sugar than the sleeve procedure.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

Many health-conscious consumers have already cut back on hamburgers, steaks, and deli meats, often by swapping in poultry or seafood. Those protein sources are better than beef, and not just because they’re linked to a lower risk of heart disease, diabetes, and cancer. Chicken and fish are also better for the environment, as their production uses less land and other resources and generates fewer greenhouse gas emissions.

And choosing seafood that’s lower on the food chain — namely, small fish such as herring and sardines and bivalves such as clams and oysters — can amp up those benefits. “It’s much better for your health and the environment when you replace terrestrial food sources — especially red meat — with aquatic food sources,” says Christopher Golden, assistant professor of nutrition and planetary health at the Harvard T.H. Chan School of Public Health. But instead of popular seafood choices such as farmed salmon or canned tuna, consider mackerel or sardines, he suggests.

Why eat small fish?

Anchovies, herring, mackerel, and sardines are all excellent sources of protein, micronutrients like iron, zinc, and vitamin B12, and heart-healthy omega-3 fatty acids, which may help ease inflammation within the body and promote a better balance of blood lipids. And because you often eat the entire fish (including the tiny bones), small fish are also rich in calcium and vitamin D, says Golden. (Mackerel is an exception: cooked mackerel bones are too sharp or tough to eat, although canned mackerel bones are fine to eat).

Small fish are also less likely to contain contaminants such as mercury and polychlorinated biphenyls (PCBs) compared with large species like tuna and swordfish. Those and other large fish feed on smaller fish, which concentrates the toxins.

It's also more environmentally friendly to eat small fish directly instead of using them to make fish meal, which is often fed to farmed salmon, pork, and poultry. Feed for those animals also includes grains that require land, water, pesticides, and energy to produce, just as grain fed to cattle does, Golden points out. The good news is that increasingly, salmon farming has begun using less fish meal, and some companies have created highly nutritious feeds that don’t require fish meal at all.

Small fish in the Mediterranean diet

The traditional Mediterranean diet, widely considered the best diet for heart health, highlights small fish such as fresh sardines and anchovies, says Golden. Canned versions of these species, which are widely available and less expensive than fresh, are a good option. However, most canned anchovies are salt-cured and therefore high in sodium, which can raise blood pressure.

Sardines packed in water or olive oil can be

• served on crackers or crusty, toasted bread with a squeeze of lemon
• prepared like tuna salad for a sandwich filling
• added to a Greek salad
• tossed with pasta, either added to tomato sauce or with lemon, capers, and red pepper flakes.

Golden is particularly fond of pickled herring, which you can often find in jars in supermarkets, or even make yourself; here’s his favorite recipe.

Bivalve benefits

Bivalves are two-shelled aquatic creatures that include clams, oysters, mussels, and scallops. Also known as mollusks, they’re good sources of protein but are quite low in fat, so they aren’t as rich in omega-3’s as small, fatty fish. However, bivalves contain several micronutrients, especially zinc and vitamin B12. Zinc contributes to a healthy immune system, and vitamin B12 helps form red blood cells that carry oxygen and keep nerves throughout the body healthy. While most Americans get enough B12, some may not.

And from a planetary health perspective, bivalves are among the best sources of animal-based protein. “Bivalves can be ‘nature positive’ because they don’t require feed and they filter and clean up water,” says Golden.

Be aware, however, that bivalves can become contaminated from runoff, bacteria, viruses, or chemicals in the water. So be sure to follow FDA advice about buying and preparing seafood safely.

Although we tend to think of coastal cities as the best places to find seafood, it’s available throughout the United States. For less-common varieties, try larger Asian markets, which often carry a wide variety of fish and bivalves, Golden suggests.

Aquatic plant foods

You can even go one step further down the aquatic food chain by eating aquatic plant foods such as seaweed and kelp. If you like sushi, you’ve probably had nori, the flat sheets of seaweed used to make sushi rolls. You can also find seaweed snacks in Asian and many mainstream grocery stores. The truly adventurous may want to try kelp jerky or a kelp burger, both sold online.

Nutrients in seaweed vary quite a bit, depending on species (kelp is one type of brown seaweed; there are also numerous green and red species). But seaweed is low in calories, is a good source of fiber, and also contains iodine, a mineral required to make thyroid hormones. Similar to terrestrial vegetables, seaweeds contain a range of other minerals and vitamins. For now, aquatic plant foods remain fringe products here in the United States, but they may become more mainstream in the future, according to Golden.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Howard LeWine, M.D., is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

When I took up running in college, a friend of mine scoffed at the idea. He hated running and was convinced runners were “wearing out” their joints. He liked to say he was saving his knees for his old age.

So, was he onto something? Does running really ruin your joints, as many people believe?

Runners can get arthritis, but is running the cause?

You may think the answer is obvious. Surely, years of running (pounding pavements, or even softer surfaces) could wear out your joints, much like tires wear out after you put enough miles on them. And osteoarthritis, the most common type of arthritis, usually affects older adults. In fact, it’s often described as age-related and degenerative. That sounds like a wear-and-tear sort of situation, right?

Maybe not. Sure, it’s easy to blame running when a person who runs regularly develops arthritis. But that blame may be misguided. The questions to ask are:

• Does running damage the joints and lead to arthritis?
• Does arthritis develop first and become more noticeable while running?
• Is the connection more complicated? Perhaps there’s no connection between running and arthritis for most people. But maybe those destined to develop arthritis (due to their genes, for example) get it sooner if they take up running.

Extensive research over the last several decades has investigated these questions. While the answers are still not entirely clear, we’re moving closer.

What is the relationship between running and arthritis?

Mounting evidence suggests that that running does not cause osteoarthritis, or any other joint disease.

• A study published in 2017 found that recreational runners had lower rates of hip and knee osteoarthritis (3.5%) compared with competitive runners (13.3%) and nonrunners (10.2%).
• According to a 2018 study, the rate of hip or knee arthritis among 675 marathon runners was half the rate expected within the US population.
• A 2022 analysis of 24 studies found no evidence of significant harm to the cartilage lining the knee joints on MRIs taken just after running.

These are just a few of the published medical studies on the subject. Overall, research suggests that running is an unlikely cause of arthritis — and might even be protective.

Why is it hard to study running and arthritis?

• Osteoarthritis takes many years to develop. Convincing research would require a long time, perhaps a decade or more.
• It’s impossible to perform an ideal study. The most powerful type of research study is a double-blind, randomized, controlled trial. Participants in these studies are assigned to a treatment group (perhaps taking a new drug) or a control group (often taking a placebo). Double-blind means neither researchers nor participants know which people are in the treatment group and which people are getting a placebo. When the treatment being studied is running, there’s no way to conduct this kind of trial.
• Beware the confounders. A confounder is a factor or variable you can’t account for in a study. There may be important differences between people who run and those who don’t that have nothing to do with running. For example, runners may follow a healthier diet, maintain a healthier weight, or smoke less than nonrunners. They may differ with respect to how their joints are aligned, the strength of their ligaments, or genes that direct development of the musculoskeletal system. These factors could affect the risk of arthritis and make study results hard to interpret clearly. In fact, they may explain why some studies find that running is protective.
• The effect of running may vary between people. For example, it’s possible, though not proven, that people with obesity who run regularly are at increased risk of arthritis due to the stress of excess weight on the joints.

The bottom line

Trends in recent research suggest that running does not wear out your joints. That should be reassuring for those of us who enjoy running. And if you don’t like to run, that’s fine: try to find forms of exercise that you enjoy more. Just don’t base your decision — or excuse — for not running on the idea that it will ruin your joints.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

The transgender population is steadily increasing. Last year, investigators reported that 1.3% of people between the ages of 18 and 24 in the United States identify as transgender, compared to 0.55% of the country’s older adults. This trend has implications for public health, and one issue in particular concerns the risk of prostate cancer in transgender women.

Because removing the prostate can lead to urinary incontinence and other complications, doctors leave the gland in place when initiating hormonal treatments to induce female sex characteristics in transitioning people. This process, which is called feminizing or gender-affirming hormonal therapy (GAHT), relies on medications and surgery to block testosterone, a male sex hormone. Prostate cancer is fueled by testosterone, and therefore GAHT lowers overall risks for the disease. But transgender women can still develop prostate cancer in ways that remain poorly understood, according to the authors of a new paper.

“More individuals are openly identifying as transgender, particularly as advances are made in reducing the discrimination and marginalization that this group has faced,” says Dr. Farnoosh Nik-Ahd, a urologist at the University of California, San Francisco, and the paper’s first author. “Thus, it’s important to understand their health outcomes and how best to care for this population.”

Dr. Nik-Ahd and her colleagues wanted better insights into prostate cancer incidence and screening rates among transgender women, so they performed a comprehensive review of the literature that generated some notable findings. One is that that the prevalence of GAHT in the transgender population is still unknown. Some studies put the figure at roughly one in every 12,000 to 13,000 people who identify as transgender. But this is likely an underestimate, the authors claim, and it’s not broken out by sex.

Questions over GAHT

Similarly, little is known about the impact of GAHT on the likelihood of developing prostate cancer, the team reported. Prostate cancer rates do appear to be lower among transgender women than they are among cisgender men (men whose gender identify matches their sex at birth). For instance, one study found just a single case of prostate cancer among 2,306 transgender women receiving routine health care at a clinic in Amsterdam, Holland, between 1975 and 2006. Another study, also from Holland, detected six cases of prostate cancer among 2,281 transgender women over 17 years, which again is less than the comparable rate among cisgender men.

But the interpretation of these rates is limited by the fact that transgender women often experience barriers to care. Nearly a third of them live in poverty, and many avoid the health system for fear of mistreatment. Some scientists suspect that estrogen given during GAHT may somehow contribute to prostate cancer development when given over long durations. However, more confirmatory evidence is needed. Worryingly, one study found that survival among transgender women with prostate cancer is worse than it is in cisgender men with the disease, yet that research lacked data on GAHT use.

Interpreting PSA values for specific populations

Dr. Nik-Ahd’s team was especially concerned about the lack of guideline recommendations for prostate-specific antigen (PSA) screening in the transgender population. None of the available guidelines worldwide mention transgender women, and the PSA cutoff of 4 nanograms per milliliter (ng/mL) of blood — which raises suspicions for prostate cancer — is specific to cisgender men. PSA levels ordinarily plummet in people taking GAHT, so the limit for what’s considered normal in transgender women should be capped at 1.0 ng/mL, the researchers propose. In the absence of more specific guidance, they also recommend that people meeting age criteria for PSA screening get tested before starting on GAHT, in order to obtain a baseline value.

Many doctors are already familiar with other common drugs that alter PSA values — in this case with screening implications for cisgender men, points out Dr. Heidi Rayala, a urologist affiliated with Beth Israel Deaconess Medical Center in Boston, and a member of the Harvard Medical School Annual Report on Prostate Diseases editorial board. For instance, PSA values drop by half in men taking finasteride or dutasteride for hair loss (or to shrink an enlarged prostate). “Doctors take extra care when interpreting PSA in cisgender men who take these drugs,” she says. “The same care needs to be taken in interpreting PSA values in transgender women. And there needs to be broader education on this topic for both primary care doctors as well as the transgender community.

Dr. Nik-Ahd agrees. “Future research should aim to understand baseline PSA values for those on gender-affirming hormones, and to understand how to navigate some of the psychosocial barriers around PSA screening so as to not stigmatize transgender patients,” she says.

About the Author

Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases

Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt

About the Reviewer

Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD

Driving along the freeway recently, a billboard caught my eye. In bold letters it proclaimed:

Milk hydrates better than water.

Wait, could this be true? And if so, should I be rehydrating with milk after a workout? And should we all have milk, rather than water, in our water bottles?

What’s behind the claim?

Unsurprisingly, the ad is sponsored by the milk industry. And while I’d never heard this claim before, the studies behind the idea aren’t particularly new or compelling. The website supporting this ad cites three small studies dating back more than a decade:

• A 2007 study enrolled 11 volunteers (five men, six women) who exercised until they were markedly dehydrated on several occasions. Each time they rehydrated with a different drink, and their urine output was measured over the following five hours. After drinking milk, the study volunteers produced less urine (and therefore retained more fluid) than with water or a sports drink (Powerade). Therefore, milk was considered to provide better hydration.
• A study published in 2016 described seven men with marked dehydration following exercise who drank fat-free milk, water, or Powerade. The results were similar.
• A 2016 study enrolled 72 healthy, well-hydrated men who drank various fluids and then had their urine production measured over the next four hours. The drinks used in this study were water, whole milk, skim milk, beer, Dioralyte (an oral rehydration solution used after fluid loss from diarrhea), tea, coffee, diet cola, regular cola, orange juice, and Powerade. The researchers found that fluid retention was best after drinking either type of milk or the oral rehydration solution; results for the other drinks were similar to water.

Sounds like milk is a winner, right? Maybe. But there are other things to consider.

The study details matter

The findings of these studies aren’t definitive. As with all research, there are important limitations. For example:

• The small number of participants in these studies means that just a few people could have an outsized impact on the results.
• Two of the three studies involved significant dehydration by intensely exercising in a warm environment, leading to several pounds of fluid loss. Therefore, the results may not apply to people engaged in more typical daily activities or workouts. In addition, the studies equated better hydration with less urine production in the hours after drinking various fluids. This is only one way to define hydration, and not clearly the best one.
• The advantage of milk reported in these studies may be too small or too temporary to matter much. For example, in the study of 72 people, milk drinkers produced about 37 ounces of urine over four hours while water drinkers produced 47 ounces. Does the 10-ounce difference have a meaningful health impact? If the study participants had been monitored for a longer period, would this difference disappear?
• The amount of milk consumed in the study of seven men would contain more than 1,000 calories. That may be acceptable for an elite athlete after hours of intensive exercise in the heat, but counterproductive and costly for someone working out for 30 minutes to help maintain or lose weight. Tap water is free and has no calories!

Hyping hydration: Many claims, little evidence

The billboard promoting milk reflects our relatively recent focus on hydration for health. This is promoted — or perhaps created — by advertisers selling sports drinks, energy drinks and, yes, water bottles. But does drinking “plenty of water” translate to weight loss, athletic performance, and glowing appearance? Does monitoring urine color (darker could indicate dehydration) and downing the oft-recommended eight glasses of water daily make a difference in our health? On the strength of evidence offered so far, I’m not convinced.

But wait, there’s more! Emotional support water bottles, a trend popularized recently in Australia, offer one part public expression of your commitment to health and one part security blanket. (Yes, it’s a thing: #emotionalsupportwaterbottle has more than 80 million views on TikTok.) And then there’s intravenous hydration on demand for healthy (and often wealthy) people convinced that intravenous fluids will improve their looks, relieve their hangovers, help with jet lag, or remedy and prevent an assortment of other ailments.

Is this focus on hydration actually helpful?

Before water bottles were everywhere and monitoring fluid intake became commonplace, medically important dehydration wasn’t a problem for most healthy people who were not rapidly losing fluids due to heat, intense exercise, diarrhea, or the like.

The fact is, drinking when thirsty is a sound strategy for most of us. And while there are important exceptions noted below, you probably don’t need fluids at hand at all times or to closely monitor daily fluid intake to be healthy. There are far more important health concerns than whether you drink eight glasses of water each day.

When is dehydration a serious problem?

Weather, exercise, or illness can make dehydration a major problem. Particularly susceptible are people who work or exercise outside in hot and humid environments, those at the extremes of age, people experiencing significant fluid loss (as with a diarrheal illness), and those without reliable access to fluids. If significant dehydration occurs, replacing lost fluids is critically important, and may even require a medical setting where intravenous fluids can be provided quickly.

The bottom line

Despite the claims of milk ads and the iffy studies justifying them, the idea of replacing water with milk for rehydration may not convince everyone: the taste, consistency, and extra calories of milk may be hard to get past.

As for me, until there’s more convincing evidence of an actual health advantage of milk over water for routine hydration, I’ll stick with water. But I’ll forego the water bottle.

Follow me on Twitter @RobShmerling

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Climate change is an escalating threat to the health of people everywhere. As emergency medicine physicians practicing in Australia and the United States, we — and our colleagues around the world — already see the impacts of climate change on those we treat.

Will we be seeing you one day soon? Hopefully not. Yet an ever-growing number of us will face climate-related emergencies, such as flooding, fires, and extreme weather. And all of us can actively prepare to protect health when the need arises. Here’s what to know and do.

How is climate change affecting health?

As the planet warms, people are seeking emergency medical care for a range of climate-related health problems, such as heat exhaustion and heat stroke, asthma due to air pollution, and infectious diseases related to flooding and shifting biomes that prompt ticks, mosquitoes, and other pests to relocate. News headlines frequently spotlight physical and emotional trauma stemming from hurricanes, wildfires, tornadoes, and floods.

We care for people displaced from their homes and their communities by extreme weather events. Many suddenly lack access to their usual medical team members and pharmacies, sometimes for significant periods of time. The toll of extreme weather often lands hardest on people who are homeless, those with complex medical conditions, children, the elderly, people with disabilities, minoritized groups, and those who live in poorer communities.

On a recent 110º Fahrenheit day, for example, a woman came to an emergency department in Adelaide, Australia complaining of a headache, fatigue, and nausea, all symptoms of heat exhaustion. She told medical staff that she had just walked for two hours in the sun to obtain groceries, as she had no car or access to public transportation. While health advisories in the media that day had advised her to stay inside in air conditioning, walking outside was only the only option she had to feed her family. For this woman and many others, well-intended public health warnings do little to reduce the risk of illness during extreme weather. Achieving safe, equitable health outcomes will require addressing access to shelter, access to transportation, and other societal factors that put people at risk of bad health outcomes.

Extreme weather contributes to large-scale health and safety issues

Increasingly, climate-related extreme weather is leading to interrupted access to medical care, contributing to later illness and death. Extreme weather can damage key infrastructure like the electrical grid, so that those relying on home medical equipment cannot use it. It may shut down health care facilities like a dialysis center or emergency room, or slow care in facilities that stay open.

People fleeing a fire or hurricane can be displaced into settings where they may have difficulty getting medical care or obtaining much-needed medicine, such as insulin, dialysis, high blood pressure treatments, and heart medicines. Such factors can worsen chronic conditions and may even cause death, particularly in people with existing medical conditions like heart failure, lung disease, and kidney disease.

How can you be ready to protect your health?

We all have a part to play in keeping ourselves and our communities well in the face of increasing dangers from climate change. Taking these steps will help.

If you or a loved one has health issues:

• Keep a printed summary handy listing all medical conditions, medications and dosages, and phone numbers for your health providers.
• If you have to leave your home, try to bring all medications with you — even bringing empty pill bottles will help a doctor trying to restart your medications.
• Store medicines in a waterproof bag in a place where you can easily find them. This will help if you need to evacuate quickly.

Think about what to do if you need to leave home quickly. Now is the time to figure out your basic emergency plan:

• Where will you go if you need to evacuate?
• How will you get there?
• How could you communicate with others if there is no electricity or phone service?
• Do you have written contact info for a few family members and friends, in case you lose your phone or the battery dies?

Finally, we all need to look out for others in our community. Check in on elderly neighbors and those around you who may be socially disconnected, and make sure that they are safe where they live and are able to access the medical care they may need when the weather turns hot, cold, smoky, fiery, snowy, wet, or windy.

Climate change is here. It is already having tangible and significant impacts on our communities and the health of people around the world. Moreover, the increased risk of climate-related extreme weather is here to stay for the foreseeable future, and we must prepare for the threats it poses to our health, both now and in decades to come. We all have a part to play — health professionals, communities, and individuals — in keeping ourselves and each other healthy and safe.

About the Authors

Kimberly Humphrey, MD, MPH, Contributor

Dr. Kimberly Humphrey is an emergency physician, a current Fellow in Climate Change and Human Health at Harvard C-CHANGE at Harvard's T.H. Chan School of Public Health, and a visiting scholar at the Harvard FXB Center. Her research focuses on the … See Full Bio View all posts by Kimberly Humphrey, MD, MPH

Caleb Dresser, MD, MPH, Contributor

Dr. Caleb Dresser is an emergency physician and assistant director of the Climate and Human Health Fellowship, cohosted by Beth Israel Deaconess Medical Center, the Harvard FXB Center, and Harvard C-CHANGE. His research focuses on understanding the health implications of climate-related … See Full Bio View all posts by Caleb Dresser, MD, MPH

Low energy, brain fog, and lung problems are a few of the lingering aftereffects reported by some people who have had COVID-19. Could gut troubles also fall among the constellation of chronic symptoms that people with long-haul COVID experience? And if so, what do experts suggest to help ease this?

What happens to the gut during a COVID infection?

As we head into the fourth year since COVID-19 became a global health emergency, hundreds of millions of people around the globe have been infected with the virus that causes it. Since 2020, we’ve known that the virus particles that cause lung illness also infect the gastrointestinal (GI) tract: the esophagus, stomach, small intestines, and colon. This can trigger abdominal pain and diarrhea, which often — but not always — clear up as people recover.

We know chronic gut problems such as irritable bowel syndrome (IBS) sometimes occur even after illness caused by microorganisms like Campylobacter and Salmonella are cured. Could this happen with COVID-19?

What is long COVID?

While most people who get COVID-19 will survive, medical science is becoming aware of a group of people suffering from lasting declines in health. Well-reported long COVID aftereffects include tiredness, breathing difficulty, heart rhythm changes, and muscle pain. But few people, even in the medical field, are aware that long COVID symptoms may include chronic diarrhea and abdominal pain.

Why might the gut be involved in long COVID?

It is not clear why chronic gut symptoms might occur after a COVID-19 infection. One possible insight is a well-known syndrome called post-infectious irritable bowel syndrome (IBS) that may occur after a stomach flu (gastroenteritis).

Long after the bug causing the illness is gone, a change in gut-brain signaling may occur. A complex network of nerves connects the gut and the brain, and controls communication between different parts of the gut. These nerves tell body organs to produce digestive juices, alert you to the need to go to the bathroom, or prevent you from having another serving of stuffing at the Thanksgiving table.

The nerve network of the gut is so complicated that it is sometimes called the second brain. When the nerves are working well, you won’t notice a thing: you eat without pain, you move your bowels with ease, you have no GI worries. But what if the nerves are not working well? Then, even if the process of digestion remains normal, you may frequently have symptoms like pain or a distressing change in your bowel movements, such as diarrhea or constipation.

Once known as functional GI disorders, these health problems are now called disordered gut-brain interactions (DGBIs). When viruses and bacteria infect the gut, experts believe they may prompt a change in gut-brain signaling that can cause a DGBI like IBS to develop.

What to do if you’re noticing long-lasting gut problems after COVID-19 infection

We still do not know conclusively if COVID-19 can cause a long-term change in gut-brain messaging that leads to IBS or other disordered gut-brain interactions. But increasing evidence suggests that GI distress lasting six months or longer might be a symptom of long COVID. While we wait for more evidence, some GI specialists, including myself, recommend trying approaches that help relieve irritable bowel syndrome and other DGBIs.

If you are suffering from chronic abdominal pain and a change in your bowel movements after having had COVID-19, talk to your primary care doctor. Many health conditions have similar symptoms, including viral or bacterial infections, inflammation, or even cancers. A thorough exam can help to rule out certain conditions.

If the problem persists, do not suffer alone or feel embarrassed to act! Seek help if severe pain or changes in bowel movements are harming your quality of life or affecting daily activities. Talk with your doctor about the possibility that your chronic gut symptoms might be a form of long COVID. Find out if they can recommend helpful treatments or suggest a referral to a GI specialist. As research continues, new information may be available.

About the Author

Christopher D. Vélez, MD, Contributor

Dr. Christopher Vélez is an attending gastroenterologist in the Center for Neurointestinal Health of Massachusetts General Hospital's division of gastroenterology and the MGH department of medicine. He focuses on neurogastroenterology and motility disorders of the esophagus, … See Full Bio View all posts by Christopher D. Vélez, MD

A tremendous buzz surrounds collagen drinks and supplements, as celebrities and influencers tout miraculous benefits for skin, hair, and nails. Since the collagen in our bodies provides crucial support for these tissues, it seems plausible that consuming collagen might lead to lush locks and a youthful glow. But what does the science say?

What is collagen?

Collagen is a major structural protein in our tissues. It’s found in skin, hair, nails, tendons, cartilage, and bones. Collagen works with other substances, such as hyaluronic acid and elastin, to maintain skin elasticity, volume, and moisture. It also helps make up proteins such as keratin that form skin, hair, and nails.

Our bodies naturally produce collagen using the amino acids from protein-rich or collagen-rich foods like bone broth, meat, and fish. But aging, sun damage, smoking, and alcohol consumption all decrease collagen production.

Collagen drinks and supplements often contain collagen from many different sources, such as fish, cattle, pigs, or chicken. Typically, they contain peptides, short chains of amino acids that help make up essential proteins in the body, including collagen itself and keratin.

What does the science say about collagen drinks and supplements?

Research on skin includes:

• A review and analysis of 19 studies, published in the International Journal of Dermatology, that had a total of 1,125 participants. Those who used collagen supplements saw an improvement in the firmness, suppleness, and moisture content of the skin, with wrinkles appearing less noticeable. That sounds promising, but it’s unclear if these skin improvements were actually due to collagen. Most of the trials used commercially available supplements that contained more than collagen: vitamins, minerals, antioxidants, coenzyme Q10, hyaluronic acid, and chondroitin sulfate were among the additional ingredients.
• A few randomized, controlled trials (see here and here) show that drinking collagen supplements with high amounts of the peptides prolylhydroxyproline and hydroxyprolylglycine can improve skin moisture, elasticity, wrinkles, and roughness. But large, high-quality studies are needed to learn whether commercially available products are helpful and safe to use long-term.

Hardly any evidence supports the use of collagen to enhance hair and nails. One small 2017 study of 25 people with brittle nails found that taking 2.5 grams of collagen daily for 24 weeks improved brittleness and nail growth. However, this small study had no control group taking a placebo to compare with the group receiving collagen supplements.

There haven’t been any studies in humans examining the benefits of collagen supplementation for hair. Currently, no medical evidence supports marketing claims that collagen supplements or drinks can improve hair growth, shine, volume, and thickness.

Should you try collagen supplements or drinks?

At this time, there isn’t enough proof that taking collagen pills or consuming collagen drinks will make a difference in skin, hair, or nails. Our bodies cannot absorb collagen in its whole form. To enter the bloodstream, it must be broken down into peptides so it can be absorbed through the gut.

These peptides may be broken down further into the building blocks that make proteins like keratin that help form skin, hair, and nails. Or the peptides may form collagen that gets deposited in other parts of the body, such as cartilage, bone, muscles, or tendons. Thus far, no human studies have clearly proven that collagen you take orally will end up in your skin, hair, or nails.

If your goal is to improve skin texture and elasticity and minimize wrinkles, you’re better off focusing on sun protection and using topical retinoids. Extensive research has already demonstrated that these measures are effective.

If you choose to try collagen supplements or drinks, review the list of ingredients and the protein profile. Avoid supplements with too many additives or fillers. Products containing high quantities of prolylhydroxyproline and hydroxyprolylglycine are better at reducing wrinkles and improving the moisture content of skin.

Consult your doctor before starting any new supplements. People who are prone to gout or have other medical conditions that require them to limit protein should not use collagen supplements or drinks.

The bottom line

Large-scale trials evaluating the benefits of oral collagen supplements for skin and hair health are not available. If you’re concerned about thinning or lackluster hair, brittle nails, or keeping skin smooth and healthy, talk to your doctor or a dermatologist for advice on the range of options.

It will also help to:

• Follow a healthy lifestyle and eat a balanced diet that includes protein-rich foods.
• If you smoke, quit.
• Limit alcohol to two drinks or less in a day for men or one drink or less in a day for women.
• Apply sunscreen daily and remember to reapply every two hours.
• Wear wide-brimmed or UV-protective hats and clothing when you’re spending a lot of time in the sun.

Follow Payal Patel on Twitter @PayalPatelMD

Follow Maryanne Makredes Senna on Twitter @HairWithDrMare

About the Authors

Payal Patel, MD, Contributor

Dr. Payal Patel is a dermatology research fellow at Massachusetts General Hospital. Her clinical and research interests include autoimmune disease and procedural dermatology. She is part of the Cutaneous Biology Research Center, where she investigates medical … See Full Bio View all posts by Payal Patel, MD

Maryanne Makredes Senna, MD, Contributor

Dr. Maryanne Makredes Senna is a board-certified dermatologist at at Beth Israel Lahey Health, and assistant professor of dermatology at Harvard Medical School. Dr. Senna founded and directs the Lahey Hair Loss Center of Excellence and … See Full Bio View all posts by Maryanne Makredes Senna, MD