Why do we age— the neuroendocrine theory of agingBy brotholtz | March 24th, 2017
A couple of years ago, I watched a TV show about a new trend of using daily injection of IGF to reverse or stop the aging process. And, of course, I am sure that you’ve heard about the hormone replacement therapy. The scientific theory for these treatments is the neuroendocrine theory of aging.
The neuroendocrine theory of aging: The neuroendocrine system refers to the complex connection between the brain and nervous systems, and the endocrine glands. The hypothalamus structure at the end of the brain regulates pituitary gland. Pituitary gland in turn regulates the glands of the body including ovaries, testes and thyroid and influences the release of hormones into circulation.
As human age, the system becomes less functional and leads to the degenerative conditions of aging. The most obvious example of age-related hormone change is menopause in women. Recent research showed that hormones, including insulin-like peptides, IGF (insulin-like growth factor), lipophilic signaling molecules and sterols are all candidate effectors of aging. Suppression of these hormones or their receptors can increase life span and delay age-dependent function decline. IGF especially is considered to be one of the key in the endocrine regulation of aging.
The neuroendocrine theory of aging is another popular theory of aging (in addition to the free radical theory of aging we discussed in the past post). I do believe that neuroendocrine change is an important piece in our aging process. Unfortunately, current hormone replacement therapy or direct IGF injection treats human body as a simple mechanic device—“the motor oil is running low and let’s add more.” When our body ages, all parts slow down. The slowing downs that we can feel and see such as menopause, skin sagging and wrinkling, loss of muscle tones are just a few aspects among many. Aging affects every cell in our body: our eyesight changes, heart gets weaker, liver and lung function reduces, and kidney function declines. Simply adding hormone to the body in order to treat some symptoms could cause havoc to other parts of the body. The extra hormone (which serve as chemical signals between cell communications) often over charges the aging cells leading to unwanted side effect (to put it mildly) such as cancer. I believe the necessity of the hormonal therapy in some cases to solve a real clinical need. However I am not a believer of using hormone to treat skin aging.
So back to the point—how to slow down the hormonal change caused aging process in woman? For the age related estrogen loss, phyto-estrogens could be a safe alternative. It has been long noted that Japanese women do not suffer as much from the menopause related symptom such as hot flashes. The observation has been attributed to the Japanese women’s phytoestrogen (i.e., soy) rich diet. Phyto-estrogens are plant-derived xenoestrogens (see estrogen) not generated within the endocrine system but consumed by eating phytoestrogenic plants. Also called “dietary estrogens”, they are a diverse group of naturally occurring nonsteroidal plant compounds that, because of their structural similarity with estradiol (17-β-estradiol), have the ability to cause estrogenic or/and antiestrogenic effects, antiestrogenic effects by sitting in and blocking receptor sites against estrogen.
One great source of phyto-estrogen is cocoa. Research has shown that chocolate contains phytoestrogens such as isoflavones and that consuming chocolate will help ameliorate the effects of depleted estrogen levels in women.
Other foods in western diet with the high phytoestrogen content were nuts and oilseeds, followed by soy products, cereals and breads, legumes, and meat products. Flax seed and other oilseeds contained the highest total phytoestrogen content, followed by soybeans and tofu. The highest concentrations of isoflavones are found in soybeans and soybean products followed by legumes, whereas lignans are the primary source of phytoestrogens found in nuts and oilseeds (e.g. flax) and also found in cereals, legumes, fruits and vegetables.
If you choose to go with dietary supplements route, be sure to choose a product rich in plant derived natural phytoestrogens.
Thanks for reading!
Dr. Connie Wan