Excellent summary of dangers of soy

[Guest guest]

Dr Barry Groves, a nutritionist from the UK, wrote an excellent

letter to our newspaper the Mail on Sunday in response to a promotion

they ran for readers to win loads of Atkins-brand low carb foods

which contain a lot of soy.

I have posted his letter below, because I thought it was an excellent

precis of the dangers of soy in an easily readable form, but it is

backed up with full references.

Hope you find this of interest

NB: Dr Groves website is www.second-opinions.co.uk

Jo

Dear Editor

Lack of joy with Atkins soy

Today's Mail on Sunday is promoting products containing unfermented

soya as part of a drive, presumably, to make us slimmer and healthier

by eating the Atkins diet.

It won't: Unfermented soya, which is used extensively in Atkins

products, is not a suitable food either for weight loss or for

health.

I realise that, as a newspaper, you are not trained in nutrition

or in health matters. So here are some examples of why your offer of

Atkins Nutritional products will harm those unlucky enough to 'win'

supplies of them:

1. Soya prevents weight loss.

Most people go on any diet to lose weight. But soya powerfully

suppresses the thyroid and lowers metabolic rate. (1) The thyroid

gland produces hormones that have a profound effect on our bodies'

metabolism - the rate at which our bodies use energy. This in turn

has implications for the cause and treatment of obesity. It

also affects such seemingly unrelated things as blood cholesterol

levels.

Twenty-five grams of soya protein isolate contains 50 - 70 mg of

isoflavones. Yet it took only 45 mg of isoflavones in premenopausal

women to exert significant biological effects, including a reduction

in hormones needed for adequate thyroid function. These effects

continued for three months after they stopped eating the soya. (2) A

lower metabolic rate makes weight gain more likely and weight loss

more difficult. Thus soya is the last thing anyone who is concerned

about their weight should eat.

2. Soya inhibits protein absorption.

Soya contains protease inhibitors that block the action of trypsin

and other enzymes needed for protein digestion. These produce serious

gastric distress and reduce protein digestion to cause chronic

deficiencies in amino acid uptake. In test animals, diets high in

trypsin inhibitors cause enlargement and pathological conditions of

the pancreas, including cancer. (3)

3. Soya upsets hormones.

Soya also decreases female reproductive hormones: oestrone, LS and

FSH. (4) And causes menstrual disturbances in premenopausal women.(5)

In 1992 the Swiss health service estimated that 100 grams of soya

protein provided the oestrogenic equivalent of the Pill.(6) And with

that in mind, what of its effects on children and men?

4. Soya harms children.

Isoflavones in infancy are probably the greatest cause for concern as

they are likely to affect the way a child develops. Soya consumption

has been linked to numerous disorders, including infertility,

increased cancer and infantile leukaemia, and studies dating back to

the 1950s showed that genistein in soya caused disrupted

hormone production in animals. (7) Laboratory studies also suggest

that isoflavones inhibit synthesis of oestradiol and other steroid

hormones. Several species of animals including mice, cheetah, quail,

pigs, rats, sturgeon and sheep displayed reproductive problems,

infertility, thyroid disease and liver disease due to dietary

isoflavones.

In 1998, investigators reported that circulating concentrations

of isoflavones in infants fed soya-based baby formula were 13,000 to

22,000 times higher than plasma oestradiol concentrations in infants

fed baby formula made with cow's milk. (8) Infants fed soya milk or

other soya products may develop hormone abnormalities such as delayed

genital formation in boys and early menstruation in girls. (8). An

infant exclusively fed on soya formula receives the oestrogenic

equivalent (based on body weight) of at least five birth control

pills per day. (9) By contrast, almost no phytoestrogens have been

detected in dairy-based infant formula or in human milk.

5. Soya increases cancer risk.

Soya increases the growth rate of breast cancer cells.(10) Soya

increases progesterone activity and more breast cell growth in

menstruating women. (11). And some researchers believe the rapid

increase in liver and pancreatic cancer in Africa is due to the

introduction of soya products there.(12)

6. Soya ulcerates the gut.

Pigs in the USA fed soya in their diets were found to have hopelessly

ulcerated intestines. Advice from the US soya industry's website

advised farmers to strictly limit soya fed to pigs (13) Although no

human trials have been done for ethical reasons, there is no reason

to suppose the same will not happen in humans.

7. Soya increases risk of deficiency diseases.

Lastly, soya beans have one of the highest phytic acid levels of any

grain or legume that has been studied.(14) This is important because

phytic acid binds with minerals to form phytates that are not

absorbed from the intestine. This leads to a wide range of

nutritional deficiency diseases. The mineral most affected by soya is

zinc. (15) Soya-based infant formula is particularly harmful because

zinc is needed for proper development and functioning of the brain

and nervous system. It also plays a role in protein synthesis and

collagen formation; it is involved in the blood-sugar control

mechanism and thus protects against diabetes; it is needed for a

healthy reproductive system. Zinc is a key component in numerous

vital enzymes and plays a role in the immune system.

The current dramatic increases in obesity, diabetes, cancers, heart

disease, etc, are a direct result of policies emanating from the USA.

This present wave of low-carb dietary advice and 'low-carb' products,

aimed at undoing the previous harm, also comes mainly from the USA.

And, as I hope I have shown above, the 'foods' used are just as

unhealthy.

What is the point in swapping one disease for another?

There is, however, a much better way. It was pioneered by a Londoner,

Banting, in 1863. Indeed it was this regime that formed the

basis for all other present low-carb diets, including Atkins.

Banting's low-carb dietary regime has a century of epidemiological

evidence and clinical trials supporting it. It doesn't rely on the

unhealthy products that Atkins does, but on natural, real foods.

Correctly constituted, it is completely healthy, efficacious and

safe.

Why not ditch US pseudo-foods and support and promote the much more

natural and healthy British way?

Yours sincerely

Barry Groves, PhD

Lecturer in obesity, diabetes and associated diseases

www.second-opinions.co.uk

References

1.Ishuzuki Y, et al. The effect on the thyroid gland of soy beans

administered

experimentally in healthy subjects. Nippon Naihunpi gakkai Zasshi

1991; 67: 622-9.

2. Cassidy A, et al. Biological Effects of a Diet of Soy Protein Rich

in Isoflavones

on the Menstrual Cycle of Premenopausal Women. American Journal of

Clinical

Nutrition 1994; 60: 333-340.

3. Rackis JJ, et al. The USDA trypsin inhibitor study. I: Background,

objectives and

procedural details. In Qualification of Plant Foods in Human

Nutrition. vol. 35,

1985.

4. Duncan AM, et al. Soy isoflavones exert modest effects in

premenopausal women.

Journal of Endocrinologic Metabolism 1999; 84: 192-7.

5. Benson JE, et al. Nutritional aspects of amenorrhea in the female

athlete. Triad

International Journal of Sports Medicine 1996; 134-45.

6. Bulletin de L'Office Fédéral de la Santé Publique, No. 28, 20 July

1992

7. Matrone G, et al. Effect of Genistin on Growth and Development of

the Male Mouse.

Journal of Nutrition 1956; 235-240

8. Setchell KD, et al. Isoflavone content of infant formulas and the

metabolic fate

of these early phytoestrogens in early life. American Journal of

Clinical Nutrition

1998; Supplement: 1453S-1461S

9. Irvine C, et al. The Potential Adverse Effects of Soybean

Phytoestrogens in

Infant Feeding. NZ Medical Journal 1995; 24: 318

10. Hseih CY, et al. Estrogenic effects of genistein on the growth of

estrogen

receptor positive human breast cancer (MCF-7) cells in vitro and in

vivo. Cancer

Research 1998; 58: 3833-8

11. Mc- DF, et al. Effects of soy-protein

supplementation on

epithelial proliferation in the histologically normal human breast.

American Journal

of Clinical Nutrition 1998; 68 (6 Suppl): 1431S-5S

12. Katz SH. Food and Biocultural Evolution: A Model for the

Investigation of Modern

Nutritional Problems. In Nutritional Anthropology. Alan R. Liss Inc.,

1987, p. 50

13. www.centralsoya.com " Soya protein content for animal feed " .

14. El Tiney AH. Proximate Composition and Mineral and Phytate

Contents of Legumes Grown in Sudan. Journal of Food Composition and

Analysis 1989; 2: 6778.

15. A summary of the many effects of phytic acid on zinc absorption

can be found in:

Leviton, . Tofu, Tempeh, Miso and Other Soyfoods: The 'Food of

the Future' -

How to Enjoy Its Spectacular Health Benefits. Keats Publishing, Inc.,

New Canaan,

CT, USA, 1982