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Last updated January 1, 2014

To Fu or Not To Fu? Soy's the Question

©2001 Melissa Kaplan, The Carousel Network, VII(1):11-12

The effect of soy - specifically, its isoflavones - on lowering "bad" cholesterol (LDL - low density lipoproteins) has been documented well enough by researchers that the FDA lets soy product manufacturers put health claims on their products, so long as the product contains at least 6.25 grams of soy protein.

The only problem with this is that the research recently reported by the American Heart Association indicates one has to ingest at least 25-50 grams of soy protein. That's about the equivalent of 4+ 8-ounce glasses of soy milk per day, less if you eat other forms of soy protein during the day. The soy milk products I currently have on hand show the following protein and serving information:

Sun Soy = 6g per 8.024 oz
Soy Silk = 6.5g per 8.16 oz
EdenSoy = 6g per 8.5 oz

Each of the nutrition data panels on these products listed a serving as being "1 cup" but each had different ml specified. To run your own calculations: 8 oz = 236.6 ml; ml x 0.034 = US ounces.]

Consuming this amount of soy protein every day can lower your cholesterol level by 5-7%. Cool. Easy. No sweat. Just replace a couple of the 8 oz glasses of water or herb tea you drink every day with 1-2 servings of soy milk, and use the rest in your soups, protein shakes, cereal, pudding, etc.

Just in case you got to thinking that that was too easy, here's a little wrinkle the panel of nutrition experts found as they reviewed 10 years worth of research data on soy and cholesterol: you need to ingest at least 40-50 milligrams of isoflavones per serving. What's the catch? The isoflavone quantity may not be listed on the carton:

Sun Soy = 33 mg/serving
Soy Silk = 40-50 mg/serving
EdenSoy = no data

Okay, so soy milk has gotten a lot tastier than the brands available 10 years ago, so drinking more of it every day isn't a problem. You've discovered the fun of munching on steamed soybeans. You now throw textured vegetable (soy) protein chunks in your homemade chili instead of some or all of the meat protein you used to use. You make it a point to (try to) eat lots of veggies and fruits instead of things loaded with animal protein and fats. You've even cut out foods that can also raise or keep elevated your LDL, such as corn, potatoes and other root vegetable. And of course you make sure to exercise several times a week (which increases your HDL level, your "good" cholesterol).

Oh. Wait. That's right. It's just about impossible for those of us with CFS/FM/Lyme to exercise enough to have any impact on our cholesterol levels.

There's also the fact that hypercholesterolemia (high serum cholesterol) is for some reason commonly found in PWCs, even if they have been maintaining a mostly or completely vegetarian diet. Since at least some of the elevated cholesterol levels have to do with something beyond our control, and our inability to exercise adequately, how much impact dietary changes will actually have is unknown...though it is better to be safe than sorry.


Or is it?
In a study published in April 2000 in the Journal of the American College of Nutrition, researchers in Hawaii found that found people who eat tofu at least twice a week may double their risk of suffering cognitive deficits in old age. They theorize that chemicals in soy may interfere with the brain's ability to make and keep nerve connections; without those connections, brain function and the brain itself changes over time. The study, following 3700 Japanese men, and their wives, since the 1960s, found that those who ate tofu two or more times a week were 1.8 times more likely to score low on mental function tests than those who ate soy occasionally. There were other factors that may have clouded the findings, such as early malnutrition, vascular problems, etc., that the researchers tried to account for, but it is clear that this is one area that needs to be researched further. Researchers think that one of the plant's chemicals is interfering with our tyrosine kinase, an enzyme that helps keep nerve cells robust and preserves the connections.


Plant Estrogens: A Thorny Dilemma
Soy isoflavones mimic estrogen and has been touted as a "natural" estrogen replacement for women who are leery about using chemical hormone replacement therapy, especially women at risk for breast cancer for whom estrogen can pose a health risk.

Other researchers are becoming increasingly aware that estrogen and the other "sex" hormones play a much wider role in our bodies, including brain function and nerve health. That's why some are looking at the effect of "natural" estrogen, such as some of the isoflavones found in soy, on brain and body.

But, at a meeting of the American Association for Cancer Research, researchers at the University of Illinois in Chicago reported that soy protein may be less effective in reducing breast cancer risk than previously thought. Researchers did find that women who regularly eat soy protein appear less vulnerable to breast cancer, and linked that protection to one particular isoflavone, genistein.

The Illinois researcher who led this latest work says tests in rodents fed soy protein stripped of isoflavones showed significantly more tumor protection than soy protein with the compounds and, further, that genistein was much less effective at blocking tumor growth than its relatively ignored sibling molecule, daidzein.


Ties that Bind
There are two other possible adverse heath effects when it comes to soy. Soy is goitrogenic: it binds iodine, preventing its uptake and use by the thyroid gland, leading to hypothyroidism. Many soy products are also high in fat; since fat interferes with calcium metabolism, high intakes may lead to calcium deficiency unless calcium in the diet is supplemented and taken at a time several hours before or after fat (soy) intake. (It is nice that some of the soy milk products are enriched with calcium but I would still recommend taking your calcium supplements at some other time.)


Tofutti it
Okay, so we can't exercise like we would if we were healthy, many of us are hypercholestereolemic, and we're already cognitively dysfunctional. Does this mean we should go ahead and increase our soy intake to help reduce the cholesterol? Well, it can't hurt our cholesterol levels. But we still need to ensure we are eating a widely varied and balanced diet, as much as our various gut dysfunctions and food sensitivities will allow.

Lon White, chief author of the Hawaii study, says that the bottom line is that isoflavones act like drugs. As consumers, we need to remember that about soy - and other herbs and medicinals we take. Keep track of your soy intake, monitor your thyroid and cholesterol, and watch your calcium intake.

Soy's Problems Continue...
Along with the goitrogenic compounds that bind iodine, leading to iodine deficiency and hypothyroidism, soy contains fat and oxalates which each, in their own way, impede the body's ability to properly utilize and metabolize dietary calcium (calcium from food and from supplements), leading to disorders related to calcium deficiency (which affects nerves, heart, muscle and other key systems and functions, as well as bone density).

Church, Susan. 2000. Soy Clobbers Cholesterol: American Heart Association backs soy as heart-healthy.

Goldstein, Jay. 1992. The Diagnosis of Chronic Fatigue Syndrome As A Limbic Encephalopathy. From, Chronic Fatigue Syndrome: The Limbic Hypothesis.

Gordon, Eric. 2000. Personal communication.

Marcus, Adam. 2000. Soy Under Fire: Two studies question its health benefits.

Oxalosis & Hyperoxaluria Foundation (OHF). Oxalate Content of Food. Last updated May 2004.

White, LR, et al. 2000. Brain Aging and Midlife Tofu Consumption. JACN April 2000, Vol 19 No 2

Copyright 2001 Melissa Kaplan. Permission to reprint in support group newsletters granted. Any other use requires permission of author. Please visit my CND site for more information on chronic neuroimmune diseases such as chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity, and more.


Brain Aging and Midlife Tofu Consumption.
White LR, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W. National Institute on Aging, NIH, USA.
JACN April 2000, Vol 19 No 2

OBJECTIVE: To examine associations of midlife tofu consumption with brain function and structural changes in late life.

METHODS: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews.

RESULTS: Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0.

CONCLUSIONS: In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.




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