Researchers at University of California-Los Angeles investigated the effects of a low-fat, high-fiber diet on 39 middle-aged, white, healthy men (50-60 yr of age). At the start they consumed their usual high-fat, low-fiber diet and then an 8-week modulation to an isocaloric low-fat, high-fiber diet.
The details of the findings on the high-fiber, low-fat diet includes:
- Mean body weight decreased by 1 kg, whereas total caloric intake, energy expenditure, and activity index were not changed
- Mean serum testosterone (T) concentration fell (P <>
- Small but significant decreases in serum free T (P = 0.0045)
- Small but significant decrease in 5 alpha-dihydrotestosterone (P = 0.0053)
- Small but significant decrease in adrenal androgens (androstendione, P = 0.0135; dehydroepiandrosterone sulfate, P = 0.0011)
- Serum estradiol and SHBG showed smaller decreases
- Parallel decreases in urinary excretion of some testicular and adrenal androgens were demonstrated
- Metabolic clearance rates of T were not changed
- Production rates for T showed a downward trend while on low-fat diet modulation
The researchers overall conclusion was clear: We conclude that reduction in dietary fat intake (and increase in fiber) results in 12% consistent lowering of circulating androgen levels without changing the clearance.
Testosterone levels reach a peak during a man's twenties. Aging and lifestyle factors such as stress, improper diet, physical inactivity, smoking, drinking and the use of prescription medications can significantly reduce these levels.
Low levels of testosterone can result in:
- sexual dysfunction
- lack of energy
- irritability and mood swings
- loss of strength or muscle mass
- increased body fat
- hot flashes
Currently, the more subtle symptoms of low testosterone are commonly attributed to stress or the natural process of aging.
The evidence shows that a low-fat diet can lower testosterone in men. Following a good diet strategy is important not only for health reasons, but also for vitality. The IAS Bulletin recently included recommendations for a good diet strategy:
- Eat moderate amounts of protein
"Protein" in Latin means "above all else." Adequate protein is a dietary necessity as it stimulates testosterone release - it's also the fundamental building block for muscle repair and growth.
- Eat more vegetables
Especially green, leafy and cruciferous vegetables such as broccoli, cauliflower, kale, Swiss chard, Brussels sprouts, green leafy lettuce and cabbage. These vegetables contain phytochemicals essential for healthy metabolism of estrogen.
- Limit your intake of refined, high-carbohydrate foods
These include simple sugars such as cookies, candy and ice cream; and starches such as breads, potatoes and pasta. Excess intake of these carbohydrates raise blood sugar rapidly, creating chronically elevated levels of the hormones insulin and cortisol. These two hormones oppose the action of testosterone and diminish its production.
- Eat healthy fats
Essential fats such as the Omega 3 fatty acids (found in fish and flaxseed) and saturated fats are essential for normal testosterone production. All steroid hormones are produced from cholesterol and when fats are deficient in the diet, this process will be inhibited. Studies clearly indicate that low fat diets result in lower testosterone levels. Those higher in protein, lower in carbohydrate, and moderate in fat cause the greatest sustained levels of testosterone.
- Take a high-quality, multi-vitamin mineral supplement
Vitamins A, E, C and B6 and zinc are all used by the body in converting prohormones to testosterone. In fact, of all the minerals found in the body, zinc is the most crucial for testosterone production. Zinc deficiency is very common in the U.S. population, especially among athletes and the aged. Not only is zinc absent in most commercially-processed foods, it can be depleted from the body by alcohol and many prescription medications including diuretics.