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Flaxseeds for Diabetes

October 8, 2013 by Michael Greger M.D. in News with 7 Comments

Drug companies hope to capitalize on the fact that the consumption of certain plants appears to lower the risk of diabetes by isolating these plants’ active components for use and sale as pharmacological agents. Though not as profitable, why don’t we just eat the plants themselves?

One plant in particular that’s now been tested is flax. We’ve known for 20 years that having ground flax in your stomach can blunt the blood sugar spike from a meal, but it’s never been tested in diabetics–until now. World Health Organization researchers published an open-label study on the effect of flax seed powder supplementation in the management of diabetes.

Diabetic subjects took a tablespoon of ground flax seeds every day for a month, and, compared to the control group, experienced a significant drop in fasting blood sugars, triglycerides, and cholesterol, as well as the most important thing, a drop in A1C level. If one’s sugars are already well controlled, though, there may be no additional benefit.

How does flax help control blood sugars? Flaxseeds may improve insulin sensitivity in glucose intolerant people. After 12 weeks of flax, researchers found a small but significant drop in insulin resistance, perhaps related to the drop in oxidant stress due to the antioxidant qualities of flaxseeds.

The study profiled in my 3-min video Flaxseed vs. Diabetes showing a tablespoon of daily ground flax seeds for a month appears to improve fasting blood sugars, triglycerides, cholesterol, and hemoglobin A1c levels in diabetics was a non-blinded, non-randomized small study. If it was some drug they were testing, I’d never prescribe it based on this one study, but this isn’t a drug. It’s just flaxseeds. There are just good side effects, so even if this study was a fluke or fraud, flaxseeds have other benefits. In the worst case scenario the seed would still end up benefiting patients who aren’t quite ready or able to reverse their diabetes completely with a plant-based diet.

Flaxseeds are calorically dense, but even adding a half cup of ground flax a day may not lead to weight gain. When 4 tablespoons a day were tested for 3 months the flax group ended up with a slimmer waist than the flaxseed oil or control group. Because of the potential of raw flax seeds to interfere with thyroid function at high doses, though, I would only recommend 2 tablespoons a day. And I would not recommend flaxseed supplementation during pregnancy.

The flaxseed study reminds me of the Prunes vs. Metamucil for Constipation one, or any of those talking about various foods that may control blood sugar (Amla Versus Diabetes), weight (Fat Burning Via Flavonoids), cholesterol (Dried Apples Versus Cholesterol), or sexual dysfunction (Watermelon as Treatment for Erectile Dysfunction). Yes, these foods may help, but why not get at the root of the problem and try to reverse the condition altogether with a healthier diet overall?

The three best books on reversing type 2 diabetes with diet are Defeating Diabetes, co-authored by my favorite dietician, Brenda Davis, and from two of my medical mentors: Dr. Neal Barnard’s Program To Reverse Diabetes Now and Dr. Joel Fuhrman’s The End of Diabetes.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2014 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, and From Table to Able.

Image credit: Jill A. Brown / Flickr

 

Flaxseeds for Prostate Cancer

October 3, 2013 by Michael Greger M.D. in News with 9 Comments

Flaxseeds for Prostate Cancer

 Why is there such a huge disparity in prostate cancer rates around the world? The incidence of malignant prostate cancer is highest in African Americans, some 30 times greater than in Japanese men, and 120 times greater than in Chinese men. The conventional thinking is that this may be due to the higher intake of animal fat and protein in the Western diet, but it could also be the protective phytoestrogens found in plant foods. There are two major types of phytoestrogens: soy isoflavones and lignans.

Researchers have found higher levels of lignans in the prostate fluids of men in countries with relatively low rates of prostate cancer and in vitro studies show lignans can slow the growth of prostate cancer cells in a petri dish, so a pilot study was performed on flaxseed supplementation in men with prostate cancer. Why flaxseeds? Because while lignans are found throughout the plant kingdom, flax has up to 800 times more than any other food.

The research team took a bunch of men with prostate cancer, about a month before they were scheduled for surgery to get their prostates removed, and put them on a relatively low fat diet with three tablespoons a day of ground flax. Though the scientists were skeptical that they would observe any differences in tumor biology in the diet-treated patients in such a short time span, they found significantly lower cancer proliferation rates and significantly higher rates of cancer cell death. That was compared to so-called “historical controls,” meaning compared to the kind of growth one typically sees in their situation, not to an actual randomized control group. A few years later, though, a controlled study was published.

Researchers enrolled men who recently had their prostates biopsied and were scheduled to have repeat biopsies in six months. Then they did the same thing as the previous study: they reduced the fat in their diet and put them on ground flaxseeds to see if it made their repeat biopsy look any different. These were men with what’s called PIN (prostatic intraepithelial neoplasia), which is like the prostate equivalent of ductal carcinoma in situ in the breast. That’s why they were getting repeat biopsies–to make sure it wasn’t spreading.

There hadn’t been much research on this kind of prostatic hyperplasia, with only four epidemiologic studies reported at the time. They yielded varying findings, with increased risk associated with higher energy, protein, and animal product intake, and decreased risk related to the consumption of alcohol, fruit, and green and yellow vegetables—in sum, a low-fat, plant-based diet, high in phytoestrogens. The researchers wanted to know if that kind of diet could be used to treat it too.

Watch my 4-min video Flaxseed vs. Prostate Cancer to see what they found. Study subjects experienced a significant drop in PSA levels (a biomarker of prostate cell growth), a drop in cholesterol (what one would expect with a lower fat diet with extra fiber), and most importantly, a significant decrease in the cellular proliferation rate. In fact in two of the men, their PSA levels dropped so much they didn’t even have to go through with the second biopsy!

Slowing the Growth of Cancer is good, but how about Cancer Reversal Through Diet? In other words, if one plant could do that, what about a whole diet full of plants? See my video series that goes from Ex Vivo Cancer Proliferation Bioassay (actually Engineering a Cure) to The Answer to the Pritikin Puzzle.

For benign prostate gland enlargement see Prostate vs. Plants, and Prostate vs. a Plant-Based Diet (with background in Some Prostates Are Larger than Others).

What about for breast cancer? See Breast Cancer Survival and Lignan Intake. More on these wonderful seeds in Flax and Fecal Flora, my smoothies (A Better Breakfast), and the oldie but goodie Just the Flax, Ma’am. What about chia? Find out which is better in Flaxseeds vs. Chia Seeds.

Since the dietary intervention involved both reducing fat intake and flaxseed consumption, how do we know the flax had anything to do with it? Given the composite nature of the intervention—both a lower fat diet and flaxseeds, it was unknown whether the effects could be attributed to flaxseed supplementation, a fat-restricted diet, or both factors working together.  To figure that out you’d have to do a study where you split men into four groups, a control group, a flaxseed only group, a lower-fat only group, and then a flaxseed and lower fat group. And that’s exactly what they did. Find out the results in my follow-up video Was It the Flaxseed, Fat Restriction, or Both?.

That reminds me of the experiment described in Is It the Diet, the Exercise, or Both? in which researchers try to tease out the individual effects of a similar composite treatment—a plant-based diet and walking—on the growth of prostate cancer cells in vitro. They both appeared to help, but diet appeared to be more powerfully protective.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2014 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, and From Table to Able.

Image credit:  / Wikimedia Commons

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