Is soy bad for you? Should men eat it? 3 things to know about adding soy to your diet

When Americans were informed of the health-destroying nature of much of what we eat, especially red meat and fatty dairy products, numerous efforts were made to find substitutes. That’s a tall order since meat and dairy have dominated our diet for many decades and we believe they are essential to meet protein and calcium requirements.

Indeed, I grew up firmly believing I needed at least three glasses of whole milk daily. In fact, to help ensure the lofty status of milk and enforce the three glasses per day rule, we had daily milk breaks when I was in first grade in 1952. Milk shared the spotlight with meat. In my family, it was mandatory that if a slab of meat appeared on your plate, you ate every bit of it, with no exceptions.

As the incidence of heart disease increased and the American diet was exposed as a key contributing factor, soy burst onto the scene with claims that it can replace the benefits of meat and dairy, but without the health-destroying baggage. At first, no one paid much attention, and soy was left largely to wild-eyed, tofu-loving vegetarians. I wasn't a vegetarian at that time and admit that my "macho demeanor" wouldn't allow me to consider allowing a morsel of soy to enter my mouth.

There also was a concerted two-fold effort by big business interests to increase the promotion of meat and dairy products with their huge advertising budgets, while at the same time attempting to destroy the public image of soy.

Despite the campaign to destroy soy, it took hold and its popularity increased to the point of being perceived as a threat to the status quo. This, in turn, inspired more effort to promote fear and disdain.

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Will eating soy add estrogen to my diet?

The assault on soy has been particularly effective with men where two arguments have been fabricated and advanced. The first is soy contains estrogen.

Technically, this is true as soy contains a form of "plant estrogen," isoflavone phytochemicals that are not the same as human estrogen. But will this "feminize" men, as some have argued?


Clinical studies have shown that eating soy does not reduce sperm count or lower testosterone levels. What's more, the dosage of isoflavones found in naturally occurring soybeans and soybean products is modest. And on the plus side, studies indicate that soy may be protective against prostate cancer.

What type of protein is found in soy?

Soybean farmer Ryan Bivens holds a sample on his farm in Hodgenville, Ky
Soybean farmer Ryan Bivens holds a sample on his farm in Hodgenville, Ky

Another bogus argument is that the plant protein soy provides is inferior to animal protein.

Wrong. Soy provides "complete" protein because it contains all the essential amino acids. Essential means your body cannot manufacture certain amino acids and it is “essential” that you get them from your diet.

Can you lift weights and compete as a strength athlete if you consume soy instead of meat and dairy products?


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There is a long list of successful competitive endurance and strength athletes who were vegetarians. In addition, considerable bona fide research supports this as well. For example, a 2020 study in the "European Journal of Clinical Nutrition" concluded: “These data suggest vegan diets are not detrimental to athletic performance and may improve endurance and muscle strength, and clinicians should consider vegan diets for exercise training programs.”

Is soy bad for you?

The campaign against soy has not been restricted to men. Women at higher risk of breast cancer and those who have had breast cancer are warned to avoid soy products. But what does the science say?

Early research results on soy and the potential to promote breast cancer in high-risk patients found mixed results. However, recent and more sophisticated research studies tell a different story. Here is a summation of recent research on this topic from Dr. Omer Kucuk, a medical oncologist and researcher from the Winship Cancer Institute at Emory University: "So far, we know that soy foods are good, soy foods are safe, soy foods prevent breast cancer, and also improve treatment results and decrease mortality in breast cancer patients."

Another ploy to spook women against soy is the bogus argument that soy causes calcium deficiencies and promotes osteoporosis. Early research found chemicals in soy that can inhibit calcium absorption. This caused soy opponents to jump on this and shout it from the rooftops, but further studies revealed this is not a problem. However, in fairness, soymilk contains less calcium than cow’s milk, and for that reason soymilk typically is fortified with calcium. Thus, soymilk and soy products do not contribute to osteoporosis.

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Thankfully, big business was unable to destroy the reputation of soy, but it is still not as mainstream as meat and dairy products, foods that can destroy our health and can cause Americans to live sicker and die quicker than folks in other industrialized countries.

Reach Bryant Stamford, a professor of kinesiology and integrative physiology at Hanover College, at

This article originally appeared on Louisville Courier Journal: Is soy bad for you? 3 things to know about adding soy to your diet