Month: July 2022

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

Hot flashes and sleep or mood changes are well-known, troublesome symptoms that may occur during perimenopause and menopause. Now, one survey suggests nearly 80% of midlife women use cannabis to ease certain symptoms, such as mood issues and trouble sleeping.

Mounting numbers of US states have legalized marijuana for medical or recreational use in recent years. This wave of acceptance runs alongside skepticism in some quarters concerning FDA-approved menopause treatment options, including hormone therapy. But a lack of long-term research data surrounding cannabis use has led one Harvard expert to question how safe it may be, even while acknowledging its likely effectiveness for certain menopause woes.

“More and more patients tell me every year that they’ve tried cannabis or CBD (cannabidiol, an active ingredient in cannabis), particularly for sleep or anxiety,” says Dr. Heather Hirsch, head of the Menopause and Midlife Clinic at Harvard-affiliated Brigham and Women’s Hospital. “Adding to its appeal is that cannabis is now legal in so many places and works acutely for a couple of hours. You don’t need a doctor’s prescription. Socially, it may be easier to justify than using a medication. But why is there a movement toward saying okay to something that has unknown long-term effects, more than something that’s been studied and proven safe?” she asks.

Survey reports on who uses cannabis, why, and how

The new Harvard-led survey, published in the journal Menopause, looked at patterns of cannabis use in 131 women in perimenopause — the often years-long stretch before periods cease — along with 127 women who had passed through menopause. Participants were recruited through online postings on social media sites and an online recruitment platform. Nearly all survey respondents were white and most were middle-class, according to income reporting.

The vast majority (86%) were current cannabis users. Participants were split on whether they used cannabis for medical reasons, recreational purposes, or both. Nearly 79% endorsed it to alleviate menopause-related symptoms. Of those, 67% said cannabis helps with sleep disturbance, while 46% reported it helps improve mood and anxiety.

Perimenopausal women reported worse menopausal symptoms than their postmenopausal peers, as well as greater cannabis use to address their symptoms. More than 84% of participants reported smoking cannabis, while 78% consumed marijuana edibles, and nearly 53% used vaping oils.

One glaring limitation of the analysis is its self-selected group of participants, which lacked diversity and might skew results. But Dr. Hirsch wasn’t surprised by the high proportion reporting regular cannabis use. “I wouldn’t be surprised if those numbers reflect the broader population,” she says.

How might cannabis help menopause symptoms?

It makes sense that midlife women reported cannabis improves anxiety, mood, and sleep, Dr. Hirsch says. The drug likely helps all of these symptoms by “dimming the prefrontal cortex, the decision-making part of our brain.”

For many women, anxiety spikes during perimenopause, she notes. Common stressors during that time, such as aging parents or an emptying nest, add to the effects of dipping hormones. “It’s that feeling of, ‘I can’t turn my brain off.’ It’s really disturbing because they get in bed and can’t fall asleep, so they’re more tired, moody, and cranky the next day,” she explains. Dimming the prefrontal cortex enables people to calm down.

Hot flashes, often cited as the most common menopause symptom, did not improve as much from cannabis use, according to survey respondents. That too makes sense, Dr. Hirsch says, because the hypothalamus — the brain region considered the body’s thermostat — isn’t believed to be significantly affected by the drug.

No research yet on long-term effects

Given a lack of clinical trials objectively testing the effectiveness and safety of cannabis to manage menopause symptoms, more research is clearly needed.

“If people are finding relief from cannabis, great. But is it safe? We think so, but we don’t know,” she says. “There are no studies of middle-aged women using cannabis for 10 years, for as long as menopause symptoms often last. Are there going to be long-term effects on memory? On lung function? We don’t know.”

About the Author

Maureen Salamon, Executive Editor, Harvard Women's Health Watch

Maureen Salamon is executive editor of Harvard Women’s Health Watch. She began her career as a newspaper reporter and later covered health and medicine for a wide variety of websites, magazines, and hospitals. Her work has … See Full Bio View all posts by Maureen Salamon

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