Month: December 2022

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

When I worked at Greenpeace for five years before I attended medical school, a popular slogan was, “Think globally, act locally.” As I write this blog about climate change and hay fever, I wonder if wiping off my computer that I’ve just sneezed all over due to my seasonal allergies counts as abiding by this aphorism? (Can you clean a computer screen with a tissue?)

Come to think of it, my allergies do seem to be worse in recent years. So do those of my patients. It seems as if I’m prescribing nasal steroids and antihistamines, recommending over-the-counter eye drops, and discussing ways to avoid allergens much more frequently than in the past. Are people more stressed out, working harder, sleeping less, and thus more susceptible to allergies? Or, are the allergies themselves actually worse? Could the worsening of climate change explain why the rates of allergies and asthma have been climbing steadily over the last several decades?

There’s more pollen and a longer pollen season

Seasonal allergies tend to be caused disproportionately by trees in the spring, grasses in the summer, and ragweed in the fall. The lengthening interval of “frost-free days” (the time from the last frost in the spring to the first frost in the fall) allows more time for people to become sensitized to the pollen — the first stage in developing allergies — as well as to then become allergic to it. No wonder so many more of my patients have been complaining of itchy eyes, runny nose, and wheezing.

In many places in the United States, due to climate change, spring is now starting earlier and fall is ending later, which, yearly, allows more time for plants and trees to grow, flower, and produce pollen. This leads to a longer allergy season. According to a study at Rutgers University, from the 1990s until 2010, pollen season started in the contiguous United States on average three days earlier, and there was a 40% increase in the annual total of daily airborne pollen. More recent research in North America shows rising concentrations of sneeze-inducing pollens and lengthening pollen seasons from 1990 to 2018, largely driven by climate change.

Climate change is increasing the potency of pollen

In addition to longer allergy seasons, allergy sufferers have other things to fret about with climate change. When exposed to increased levels of carbon dioxide, plants grow to a larger size and produce more pollen. Some studies have shown that ragweed pollen, a main culprit of allergies for many people, becomes up to 1.7 times more potent under conditions of higher carbon dioxide. With warming climates, the geographic distribution of pollen-producing plants is expanding as well; for example, due to warmer temperatures, ragweed species can now inhabit climates that were formerly inhospitable.

Other unfortunate consequences of climate change, which we are already witnessing, include coastal flooding as the arctic ice sheets melt, causing the sea levels to rise; and more extreme weather, such as storms and droughts. With the increased coastal flooding, mold outbreaks are more common, which can trigger or worsen allergic reactions and asthma. More extreme weather events, such as thunderstorms, are associated with an increase in emergency department visits for asthma attacks. (It is unclear why this is the case, but one theory suggests that the winds associated with thunderstorms kick up a tremendous amount of pollen.) Allergies and asthma are closely associated, with many people, this author included, having “allergic asthma” that is likely to worsen as climate change progresses.

So what can an allergy sufferer do?

Even as the allergic environment changes in conjunction with our climate, there are steps you can take to manage the impact of seasonal allergies and reduce sneezing and itchy eyes.

• Work with your doctor to treat your allergies with medications such as antihistamines, nasal steroids, eye drops, and asthma medications if needed. If you take other medications that may interact with over-the-counter allergy medications such as Benadryl or Sudafed, let your doctor know.
• Discuss with your doctor whether you would benefit from allergy testing, a referral to an allergist, or prevention methods like allergy injections or sublingual immunotherapy, which, by exposing your body in a controlled manner, slowly conditions your immune system not to respond to environmental allergens.
• Track the local pollen count and avoid extended outdoor activities during peak pollen season, on peak pollen days. However, most doctors would agree that it isn’t healthy to cut back on exercise, hobbies, or time in nature, so this is a less than satisfying solution at best. You could plan for an indoor exercise program on high-pollen days.
• Wash clothing and bathe or shower after being outdoors to remove pollen.
• Close windows during peak allergy season or on windy days.
• Wear a mask when outdoors during high pollen days, and keep car windows rolled up when driving.
• If your house has been flooded, be on the lookout for mold. There are services that you can hire that will inspect your home for mold, and remove the mold if it is thought to be harmful.
• Have as small a carbon footprint as possible and plant trees. Even though they are responsible for some of the pollen that many of us choke and gag on each spring, summer, and fall, trees contribute to their environment by taking in carbon dioxide and producing the oxygen we breathe, thereby improving air quality. We have to protect and plant trees, even as allergy sufferers, as climate change is arguably the biggest threat that we, as a species, now face.

About the Author

Peter Grinspoon, MD, Contributor

Dr. Peter Grinspoon is a primary care physician, educator, and cannabis specialist at Massachusetts General Hospital; an instructor at Harvard Medical School; and a certified health and wellness coach. He is the author of the forthcoming book Seeing … See Full Bio View all posts by Peter Grinspoon, MD

Imagine this as a morning routine that replaces your first cup of coffee:

You wake up feeling a bit foggy, so you slip on a wearable device that looks like an extra-thick headband. You turn on the power source and settle in while electrical current flows into your brain. Twenty minutes later, feeling more focused and energized, you start your busy day feeling grateful for this new technology.

If this scenario sounds strange to you, I’m with you. And yet, hype around transcranial direct current stimulation (tDCS) is growing for an expanding list of conditions such as depression, ADHD, and even Alzheimer’s disease. A recent ad for one tDCS device urges you to “elevate your performance.” But before you give this a try, read on.

What is transcranial direct current stimulation?

Brain stimulation therapies aim to activate or inhibit parts of the brain. tDCS has been around for years, but its popularity has spiked over the last decade.

tDCS devices use headgear that may look like a swim cap or headband to position electrodes against the scalp. When a power source is switched on, the electrodes deliver low levels of electrical current to the brain. A typical session lasts 20 to 30 minutes and may be repeated over days or weeks.

Three better-known brain stimulation therapies are:

• Transcranial magnetic stimulation (TMS): A device worn over the forehead stimulates specific areas of the brain by changing nearby magnetic fields. TMS is cleared by the FDA to treat depression that hasn’t responded to standard medicines, and for obsessive-compulsive disorder.
• Electroconvulsive therapy (ECT): An electric current flowing through electrodes placed at specific locations on the scalp causes a brief seizure while a patient is under anesthesia. In use since the late 1930s, ECT can be highly effective for severe depression that hasn’t responded to standard therapies. It uses higher levels of electrical current than tDCS. That’s why it requires close medical supervision and is generally administered in a hospital or specialized clinic.
• Deep brain stimulation (DBS): Electrodes surgically implanted in specific areas of the brain generate electrical pulses. DBS is used to treat conditions such as Parkinson’s disease, epilepsy, or tremors that don’t improve with medicines.

What claims are made for tDCS?

The brain normally functions by sending and receiving tiny electrical signals between nerve cells. Stimulating specific regions of the brain with low levels of electricity might improve focus or memory, mood, or even dementia, according to tDCS advocates.

Some claims say tDCS can

• improve mental clarity, focus, and memory
• increase energy and motivation
• relieve so-called brain fog following COVID-19, Lyme disease, or other conditions
• reduce depression or anxiety
• reduce cravings among smokers or people with drug addiction
• improve symptoms of ADHD or Alzheimer’s disease.

Does tDCS work?

The jury is still out. Research suggests that tDCS holds promise for certain conditions, but techniques tested through research may differ from devices sold commercially for at-home use. For example, electrodes may be positioned more precisely over an area of the brain, and how current is delivered, session length, or number of sessions may differ.

Currently, small, short-term studies show that tDCS may benefit people with:

• Depression: An analysis of 10 randomized trials found some participants were more likely to report fewer symptoms of depression, or remission of depression, after a course of tDCS treatment compared with sham treatment.
• Alzheimer’s disease: A review of seven studies found that tDCS lasting 20 to 40 minutes improved memory and other cognitive measures in people with mild to moderate Alzheimer’s disease.
• ADHD: One randomized trial of 64 adults with ADHD found improved attention after 30 minutes of tDCS daily for a month.

The FDA has not cleared tDCS for any health condition, and it is considered investigational. More research with positive results and reassuring safety data are needed before tDCS gets a thumbs-up from regulators.

That’s probably why some ads for tDCS note in fine print that it is not a medical device and is only for recreational use.

Does tDCS have downsides?

While the FDA assesses tDCS as safe for adults, there are downsides to consider. For example, treatment may cause itching, irritation, or small burns at the sites of the electrodes. Some users complain of fatigue or headache.

There are no large, long-term studies of tDCS, so overall safety is uncertain. Some experts believe at-home use raises many questions, such as how much of the brain beyond targeted areas is affected, what inconsistent approaches to tDCS use might do, and how long changes in the brain — intended or not — could last.

Very limited research has been done in children. So, the consequences for a child’s developing brain aren’t clear.

Finally, tDCS devices can be expensive (several hundred dollars or more), and generally are not covered by health insurance.

The bottom line

It’s not yet clear how tDCS should be used, or who is most likely to benefit from it. If you’re interested in pursuing tDCS, understand that there’s still a lot we don’t know.

If you’re more skeptical and risk-averse (like me), you may want to wait for more definitive research regarding its benefits and risks — and for now, stick with your morning coffee to clear your mind.

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

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

When you first learned the facts about pregnancy — from a parent, perhaps, or a friend — you probably didn’t learn that up to one in three ends in a miscarriage.

What causes miscarriage? How is it treated? And why is appropriate health care for miscarriage under scrutiny — and in some parts of the US, getting harder to find?

What is miscarriage?

Many people who come to us for care are excited and hopeful about building their families. It’s devastating when a hoped-for pregnancy ends early.

Miscarriage is a catch-all term for a pregnancy loss before 20 weeks, counting from the first day of the last menstrual period. Miscarriage happens in as many as one in three pregnancies, although the risk gradually decreases as pregnancy progresses. By 20 weeks, it occurs in fewer than one in 100 pregnancies.

What causes miscarriage?

Usually, there is no obvious or single cause for miscarriage. Some factors raise risk, such as:

• Pregnancy at older ages. Chromosome abnormalities are a common cause of pregnancy loss. As people age, this risk rises.
• Autoimmune disorders. While many pregnant people with autoimmune disorders like lupus or Sjogren’s syndrome have successful pregnancies, their risk for pregnancy loss is higher.
• Certain illnesses. Diabetes or thyroid disease, if poorly controlled, can raise risk.
• Certain conditions in the uterus. Uterine fibroids, polyps, or malformations may contribute to miscarriage.
• Previous miscarriages. Having a miscarriage slightly increases risk for miscarriage in the next pregnancy. For instance, if a pregnant person’s risk of miscarriage is one in 10, it may increase to 1.5 in 10 after their first miscarriage, and four in 10 after having three miscarriages.
• Certain medicines. A developing pregnancy may be harmed by certain medicines. It’s safest to plan pregnancy and receive pre-pregnancy counseling if you have a chronic illness or condition.

How is miscarriage diagnosed?

Before ultrasounds in early pregnancy became widely available, many miscarriages were diagnosed based on symptoms like bleeding and cramping. Now, people may be diagnosed with a miscarriage or early pregnancy loss on a routine ultrasound before they notice any symptoms.

How is miscarriage treated?

Being able to choose the next step in treatment may help emotionally. When there are no complications and the miscarriage occurs during the first trimester (up to 13 weeks of pregnancy), the options are:

Take no action. Passing blood and pregnancy tissue often occurs at home naturally, without need for medications or a procedure. Within a week, 25% to 50% will pass pregnancy tissue; more than 80% of those who experience bleeding as a sign of miscarriage will pass the pregnancy tissue within two weeks.

What to know: This can be a safe option for some people, but not all. For example, heavy bleeding would not be safe for a person who has anemia (lower than normal red blood cell counts).

Take medication. The most effective option uses two medicines: mifepristone is taken first, followed by misoprostol. Using only misoprostol is a less effective option. The two-step combination is 90% successful in helping the body pass pregnancy tissue; taking misoprostol alone is 70% to 80% successful in doing so.

What to know: Bleeding and cramping typically start a few hours after taking misoprostol. If bleeding does not start, or there is pregnancy tissue still left in the uterus, a surgical procedure may be necessary: this happens in about one in 10 people using both medicines and one in four people who use only misoprostol.

Use a procedure. During dilation and curettage (D&C), the cervix is dilated (widened) so that instruments can be inserted into the uterus to remove the pregnancy tissue. This procedure is nearly 99% successful.

What to know: If someone is having life-threatening bleeding or has signs of infection, this is the safest option. This procedure is typically done in an operating room or surgery center. In some instances, it is offered in a doctor’s office.

If you have a miscarriage during the second trimester of pregnancy (after 13 weeks), discuss the safest and best plan with your doctor. Generally, second trimester miscarriages will require a procedure and cannot be managed at home.

Red flags: When to ask for help during a miscarriage

During the first 13 weeks of pregnancy: Contact your health care provider or go to the emergency department immediately if you experience

• heavy bleeding combined with dizziness, lightheadedness, or feeling faint
• fever above 100.4° F
• severe abdominal pain not relieved by over-the-counter pain medicine, such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil). Please note: ibuprofen is not recommended during pregnancy, but is safe to take if a miscarriage has been diagnosed.

After 13 weeks of pregnancy: Contact your health care provider or go to the emergency department immediately if you experience

• any symptoms listed above
• leakage of fluid (possibly your water may have broken)
• severe abdominal or back pain (similar to contractions).

How is care for miscarriages changing?

Unfortunately, political interference has had significant impact on safe, effective miscarriage care:

• Some states have banned a procedure used to treat second trimester miscarriage. Called dilation and evacuation (D&E), this removes pregnancy tissue through the cervix without making any incisions. A D&E can be lifesaving in instances when heavy bleeding or infection is complicating a miscarriage.
• Federal and state lawsuits, or laws banning or seeking to ban mifepristone for abortion care, directly limit access to a safe, effective drug approved for miscarriage care. This could affect miscarriage care nationwide.
• Many laws and lawsuits that interfere with miscarriage care offer an exception to save the life of a pregnant patient. However, miscarriage complications may develop unexpectedly and worsen quickly, making it hard to ensure that people will receive prompt care in life-threatening situations.
• States that ban or restrict abortion are less likely to have doctors trained to perform a full range of miscarriage care procedures. What’s more, clinicians in training, such as resident physicians and medical students, may never learn how to perform a potentially lifesaving procedure.

Ultimately, legislation or court rulings that ban or restrict abortion care will decrease the ability of doctors and nurses to provide the highest quality miscarriage care. We can help by asking our lawmakers not to pass laws that prevent people from being able to get reproductive health care, such as restricting medications and procedures for abortion and miscarriage care.

About the Authors

Sara Neill, MD, MPH, Contributor

Dr. Sara Neill is a physician-researcher in the department of obstetrics & gynecology at Beth Israel Deaconess Medical Center and Harvard Medical School. She completed a fellowship in complex family planning at Brigham and Women's Hospital, and … See Full Bio View all posts by Sara Neill, MD, MPH

Scott Shainker, DO, MS, Contributor

Scott Shainker, D.O, M.S., is a maternal-fetal medicine specialist in the Department of Obstetrics and Gynecology at Beth Israel Deaconess Medical Center (BIDMC). He is also a member of the faculty in the Department of Obstetrics, … See Full Bio View all posts by Scott Shainker, DO, MS

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