One man ate fish every day for a year and his health didn't really change, but experts say there can still be benefits to the fats.
By Korin Miller, Self
You’ve probably heard at some point that it’s a good idea to try to get a decent amount of omega-3 fatty acids
in your diet. Omega-3s are essential fats, meaning your body needs to
get them from food, and they’re found in things like fish, walnuts, and leafy vegetables. They’re also thought to help prevent heart disease and stroke, as well as depression.
[post_ads]With
that in mind, one man decided to eat fish every day for a year to see
what kind of impact it would have on his body. Paul Greenberg captured
the experience in a new Frontline documentary called The Fish on My Plate.
Greenberg met with a doctor before and after his year of fish eating to
track his progress. “I've got slightly elevated blood pressure. I've
got cholesterol issues. I have depression
issues. I have sleep issues, and I don’t like it," he says in the
documentary. "So I started to listen to the soft purr of the omega-3
industry: This is everything they’re supposed to fix."
So,
he embarked on his experiment. But, at the end, his doctor says it
really didn’t change anything. Greenberg revealed that his cholesterol
ratio was the same and his triglyceride level—the amount of a fat in
the blood—was the same. However, his blood pressure went up a little,
and he had elevated mercury levels which a biologist told Greenberg was
“slowing your thinking and hurting your memory.” (All fish contain at
least traces of mercury, which is why the FDA recommends people only eat 2 to 3 servings a week. The United States Department of Agriculture
(USDA) recommends that people eat fish twice a week.) The debate is
still on as to whether omega-3s are the wonder nutrients people say they
are.
First, here’s an omega-3 fatty acids refresher:
Omega-3 fatty acids are a group of polyunsaturated fats. The Nutrition Source
from the Harvard T.H. Chan School of Public Health breaks them down:
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) mainly come
from fish, while Alpha-linolenic acid (ALA) is found in vegetable oils
and nuts, flax seeds, leafy vegetables, and some animal fat.
Omega-3s
provide the starting point for making hormones that regulate blood
clotting, contraction and relaxation of artery walls, and inflammation,
and also bind to receptors in cells that regulate genetic function.
Omega-3 fats have been shown to help prevent heart disease and stroke,
may help control lupus, eczema, and rheumatoid arthritis, and may play
protective roles in cancer and other conditions, according to The
Nutrition Source.
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However, while the
USDA recommends that people eat fish twice a week, it doesn’t recommend
that people try to get a certain level of omega-3 fatty acids in their
daily diet. It also prohibits
companies from boasting on their food labels that certain products are
"high in," “rich in,” or an “excellent source of” DHA or EPA.
Many people try to get omega-3s through fish oil supplements. However, the American Heart Association
announced in March that they “may be reasonable” for people who have
had a heart attack or heart failure, but “there is a lack of evidence
that omega-3 fish oil supplements prevent cardiovascular diseases in the
general population.”
Experts aren’t surprised that Greenberg didn’t see a big health change with his experiment.
Kathleen
Fairfield, M.D., Dr.P.H., a physician-scientist at Maine Medical Center
with a background in nutritional epidemiology, tells SELF that she’s
not surprised that the health metrics Greenberg measured didn’t change.
“Many of the benefits of eating fish that is high in omega-3s are not
expected to be apparent in cholesterol or blood pressure measurements,”
she says. “We think that reducing the risk of sudden death from abnormal
heart rhythms in people with known heart disease
(recent heart attack, for example) is one of the major benefits.”
Fairfield says she would have thought that Greenberg’s triglycerides
would be lower, but his levels depend on his genetics and what else he
was eating.
Deena Adimoolam, M.D., an
endocrinologist specializing in diabetes and metabolism at Mount Sinai
Medical Center, tells SELF she’s also not shocked by the findings.
“There have already been large research studies performed over the years
to evaluate the health benefits of omega-3-fatty acids which have
provided non-conclusive results,” she says. This research data looked at
many people who were followed for years in some cases and were
carefully designed to study whether omega-3-fatty acids lead to a
specific health change. “I trust this data, more than I trust the story
of one individual who is studied over one year, though the end results
were similar,” she says.
[post_ads]Ruth Kava,
Ph.D., senior nutrition fellow at the American Council on Science and
Health, tells SELF that it also matters what Greenberg was eating
beforehand. If he already ate fish
once or twice a week before his experiment, it’s unlikely he would see a
change in his overall health, she says. While she says that eating fish
every day for a year isn’t necessarily a bad thing, she also points out
that omega-3s aren’t an end-all be-all when it comes to good health—and
neither is any other one food or nutrient.
“People tend to think of things as this is or isn’t a superfood, but I
don’t think that we have any superfoods, really,” she says.
The research on the benefits of omega-3s is inconclusive, but eating fatty fish can still be beneficial.
Fairfield
says the belief that omega-3s are wonder-fats started with the
observation that there was less heart disease in populations who ate a
lot of fatty fish. Then, observational studies (i.e. studies in which
researchers draw conclusions from looking at a population, but not
changing anything) that asked people to report how much fish they ate
also showed that people who ate more fatty fish had less heart disease.
However, that research shows correlation, not causation—meaning,
scientists can’t prove that eating fish causes a decrease in heart
disease, there is simply an association. “It's difficult to conduct a
randomized controlled trial of fish consumption and measure results over
many years in people with different genetic makeups, which is what we
really would need to do to understand how eating fish benefits certain
types of people over time,” Fairfield says.
[post_ads]That doesn’t mean omega-3s won’t do anything for you. Adimoolam notes that research has found that those who have established coronary artery disease
may have a reduced risk of death due to heart disease or sudden cardiac
death by having 250 milligrams a day of EPA and DHA. DHA
supplementation during pregnancy is also important for fetal brain health and maturation, she says.
As for claims that omega-3 fatty acids can help reduce depression,
Adimoolam says there are no good longitudinal studies to back this up.
“The studies that are out there are quite small and not long,” she says.
While there are more studies to suggest that omega-3-fatty acids can
help decrease a person’s risk of dementia, she says that data is not
conclusive. “The larger randomized trials did not show that omega-3
supplementation improved cognitive performance,” she says.
Fairfield
says “it’s possible” that regularly having omega-3s reduces the risk of
developing heart disease and other vascular disease, although it hasn’t
really been proven yet. And, she points out, there’s a potential
indirect effect: “If it keeps people from eating red meat, then that is
even better.” (Studies have linked red meat consumption to colorectal cancer, digestive tract inflammation, and an increased risk of stroke.)
For the average person, Kava recommends trying to eat fatty fish like salmon,
trout, and mackerel once or twice a week. If fish isn’t your thing, she
says putting ground flax seed on your cereal in the morning can also
give you a boost. She also recommends taking a pass on fish oil supplements unless your doctor specifically recommends them: “I’d rather see people get their nutrition from food.”
