posted on Dec, 13 2019 @ 07:50 AM
And on soy -
Depending on where you’re coming from, soy-based foods like tofu, soy milk, miso, tempeh, and edamame may sound like classic "health" foods. But to
some, these grocery store items have developed scary reputations for their purported "disease risk." We’ve all heard about the scary studies that
say eating soy can mess with your hormones and thyroid, and even cause cancer!
As is often the case when it comes to nutrition, the answers aren’t black and white. But for the most part, soy-based foods are some of the best
foods you can eat on the planet. Soybeans provide a plant-based protein source; a slew of vitamins and minerals crucial for reducing risk of chronic
disease; and fiber that helps you fill up and feel satisfied."
While some small, poorly designed studies have made inflammatory headlines over the years, it’s important to think about all foods in context.
Eating plant-based foods in their closest-to-nature (a.k.a. least processed) form? Super nutritious. But taking supplements made with the compounds in
soybean? Not so much.
That's where health risks have been seen - not in eating the food itself, but in supplementation. Supplementation linked to increased disease risk,
while real, whole foods are linked to decrease.
In the FAT-phobic 1990s, when soy foods first started really hitting it big many experts believed that soy had the power to fight problems like
obesity, heart disease, and even cancer. In Asia where a lot of soy is consumed studies showed that these populations had significantly lower rates of
obesity, heart disease, and breast cancer compared to people in the U.S. Clearly, soy was the miracle food! Not necessarily. Those studies only looked
at associations, not causation. Just because people who consume a lot of soy also happen to be healthier than people who don’t eat soy doesn’t
automatically mean that soy is the key to their superior state. Countless other factors — from genetics, to lifestyle, to the rest of their diet —
also play a role.
When researchers began taking a closer look to find out what made soy so healthy, they ran into some surprises. Soy, it turned out, contains
estrogen-like compounds called isoflavones. And some findings suggested that these compounds could promote the growth of some cancer cells, impair
female fertility, and mess with thyroid function.
At the same time, other studies were still showing that soy consumption could cure high cholesterol and help women cope with the symptoms of
menopause. Add it all up, and you can see how this little green bean became a source of mass dietary confusion.
The majority of recent, high-quality studies have found that soy doesn’t increase breast cancer risk, and very high consumption could even offer
some protection. A PLoS One meta-analysis of 35 studies found that soy intake lowered breast cancer risk for women in Asian countries; among U.S.
women, soy consumption and breast cancer risk were unrelated.
Eating soy could help protect against other types of cancer, too. Findings show that soy consumption may slightly lower the risk for gastrointestinal
cancers and have a protective effect in prostate cancer survivors. Eating a high-fiber diet is also tied to lower colon cancer rates, and soyfoods
like edamame and tempeh both have plenty of roughage.
Soy appears to be beneficial for fertility, as long as you don’t eat too much. Women undergoing in vitro fertilization who have environmental
exposure to BPA are more likely to get pregnant if they also ate soy. That’s likely because soy’s isoflavones help neutralize the BPA’s
Just don’t go overboard. Consuming over 100mg of soy isoflavones (the equivalent of 6-ounces uncooked tempeh or 16 cups soy milk) daily was linked
to reduced ovarian function, found a Journal of Nutrition review. But moderate soy consumption didn’t pose a problem.
As for soy solving hot flash problems? It might help, but not for everyone. Among women whose bodies produce the soy metabolite equol, those who ate
the most soy experienced significantly fewer hot flashes and night sweats compared to those who ate the least, found one Menopause study. (Between 20%
and 50% of North American and European women produce equol. Some research centers can test for it in a urine sample, but there’s an easier option:
Try adding soy to your diet for four to six weeks and see what happens. If it helps, you produce equol. If it doesn’t, you probably don’t, the
study authors say.)
Soy foods don’t affect thyroid function in people with healthy thyroids, found a Loma Linda University review of 14 studies. But if you have an
underactive thyroid, you might want to watch how much soy you eat. Soy foods have been shown to interfere with the body’s absorption of thyroid
medication — but only if you overdo it, suggests a 2016 Nutrients review. The evidence is still far from conclusive, but experts still advise to
wait at least four hours after consuming soy to take your thyroid medicine.
Eating soy in place of meat will probably protect your heart. Early research suggested that soy could help lower levels of bad cholesterol. But more
recent findings have shown that might not be the case, and in 2008, the American Heart Association said that there wasn’t enough evidence to say for
sure that soy lowered the risk of heart disease.
Still, it’s safe to assume that soy has some benefits going for it. In general, replacing animal foods with plant foods like soy lowers saturated
fat intake and ups fiber intake, both of which are help your heart. In other words, swapping that steak out for tofu or tempeh is a heart-smart move.
But having steak followed by a bowl of soy ice cream for dessert probably won’t be as helpful.
All of soy’s potential benefits come with an important caveat: To reap them, you need to pick minimally processed forms of soy — think tempeh,
tofu, miso, and edamame.
These foods serve up soy’s entire nutritional package without added sugar, unhealthy fats, sodium, or preservatives that you usually find in highly
Soy frankenfoods like meat analogs, soy bars, soy yogurts, or protein powders usually only contain soy protein isolates, rather than nutrition from
the whole soybean. Just as other processed foods are lower in nutrient density, removing the protein from the other enzymes and bacteria needed for
digestion affects the nutritional quality.
As for how often you should eat soy? As with all foods, moderation is the way to go. Generally, three to five servings of minimally processed soy
foods per week are perfectly fine.