Dr. Oz has done it again. On yesterday's Oprah show he shared some really helpful information about how to prevent colon cancer (by eating high fiber foods of course), then followed it up with poor advice: regular aspirin use.
In doing research for this blog post I've found quite a few studies do show aspirin and other NSAIDS (Non Steriodal Anti-Inflammatory Drugs) have been demonstrated to modestly lower risk of colon and colorectal cancer, so I see where Dr. Oz is coming from. But remember, aspirin is a drug, and like any other drug, it has very serious side effects when taken regularly.
One of those side effects is folic acid deficiency. This is pretty ironic, since folic acid plays an enormous role in fighting heart disease and other cancers. Sounds like cutting off your nose to spite your face.
And then of course, most of us are familiar with the aspirin-ulcer connection. It's a biggie.
Speaking of bleeding, aspirin interferes with the body's ability to form blood clots (through platelets). This is often hailed as a blessing, as blood clots can lead to heart attack and stroke. Yet this same mechanism can - and often does - prevent the body from forming life-saving blood clots, which is why an ER doctor will not push aspirin the way a heart doctor will. (I think it's time for the two to have a talk. Heart specialists seem to have no clue how many people end up in the ER from taking aspirin.)
Maybe the worst side effect of taking aspirin regularly is Leaky Gut Syndrome. You really don't want that. Leaky Gut gives us auto-immune disorders like asthma, rheumatoid arthritis, Type I diabetes, cystic fibrosis, irritable bowel, colitis, Crohn's disease, frequent migranes, Chronic Fatigue Syndrome, lupus, candida and fibromyalgia - to name a few. It also gives us food allergies, especially to gluten (wheat protein).
The American College of Gastroenterology has this to say about aspirin:
"Aspirin and other NSAIDS have been found to cause damage to the lining (or mucosa) of the digestive tract primarily in the stomach and upper intestine. This damage can result in an ulcer or intestinal bleeding. Although this can happen to an individual who is an infrequent user of aspirin or NSAIDs, it is of a much greater concern in frequent users, and those consuming higher dosages of these medications."
Messing with your gut mucosa is a good way to develop Leaky Gut Syndrome, and thus, one or more auto-immune diseases.
So if you want to prevent colon cancer without jeopardizing the rest of your body, stick to the high fiber diet. It works, and if you increase the amount of fiber you eat slowly over time, there are no side effects.
I promise this will be the last blog post on soy foods for a long time. Even though I am a strong advocate of a plant-based diet (vegetarian or vegan), I don't believe soy foods are any more essential to such a diet than garbanzo beans. I'm not saying soy foods aren't great - garbanzo beans are great too - they're just not the focus of this blog. A healthy plant-based diet is possible with or without soy foods.
However, there is some confusion regarding soy foods and fertility. Because soy is loaded with isoflavones (plant-estrogens that can mimic estrogen), it is believed to affect the likelihood of pregnancy. Some studies have shown soy estrogens have no impact whatsoever on a woman trying to conceive, as soy foods do not interfere with menstrual cycles or ovarian function.
This makes sense because soy estrogens (along with other plant-estrogens) only raise estrogen levels when they are low. This also makes sense when we look at Asian women, who consume more soy foods than any other people group and yet have an extremely low prevalence of infertility. So low in fact, certain Asian countries have to put limits on population growth. (Obviously, soy is not hindering fertility in China).
There is a recent study (July 2008) that has linked soy foods with a decreased sperm count in men (published in the Journal of Human Reproduction). However, they found that men who were overweight or obese experienced a significantly lower sperm count than men who had healthy weights. One of the reasons for this is because fat cells, even in men, produce estrogen, which can hinder sperm production in men. Considering that 72% percent of the men with decreased sperm counts were overweight or obese, I would say this seems to be more of an impediment to fertility than soy consumption.
On a personal note, my husband and I both consumed tofu pretty regularly before we had our daughter, and we had no problem getting pregnant. (That was also when my husband was in the best shape of his life!)
So I would conclude that a healthy weight in men is more important than soy intake. And a plant-based diet - with or without soy - is the best fertility diet.
Ladies, if you haven't been convinced that soy and phytoestrogens from soy products are beneficial yet, here's more news: the estrogens found in soy and soy protein prevent breast cancer.
A major study published in June's edition of the American Journal of Clinical Nutrition (Am J Clin Nutr 89: 1920-1926, 2009) studied the diets of 73,223 Chinese women over a period of 7.4 years. They found that women who consumed the most soy estrogens, or isoflavones, from food were 59% less likely to develop breast cancer than women who consumed the least. Also, adolescent girls who consumed the most isoflavones from soy foods were 43% less likely to develop premenopausal breast cancer than girls who consumed fewer soy protein.
In the words of the study authors, "This large, population-based, prospective cohort study provides strong evidence of a protective effect of soy food intake against premenopausal breast cancer."
The reason soy estrogens work to prevent breast cancer is because isoflavones have anti-estrogenic - as well as anticarcinogenic - properties. Soy estrogens don't mimic estrogen in the body as many people think they do (unless estrogen levels are dangerously low), but actually lower estrogen levels by keeping estrogen from entering the cells. By blocking cell receptors, soy estrogens keep estrogen levels from climbing high enough to encourage the growth of cancer cells. Also, isoflavones have cancer-fighting properties to boot.
Soy is a huge area of confusion in popular culture (in the U.S.) but not in scientific circles - now you can see why. If you need more encouragement, see past posts citing studies on soy and reproductive cancer. There are tons!
So whether it's tempeh, tofu, soy milk, or edamame - enjoy worry free.
Labels: soy estrogens