Testosterone and Breast CancerAugust 26, 2019
Testosterone and Cardiovascular DiseaseAugust 26, 2019
Alzheimer’s Disease is most assuredly at the top of dreaded diagnoses for both women and men.
It is a neurodegenerative disorder associated with accumulation of Beta amyloid (plaque) and tau proteins (tangles). Beta amyloid has been called the “Darth Vader” of Alzheimer’s. 5 million Americans suffer currently; in 2050, the number is estimated to range from 11-16 million. It is the 6th leading cause of death. Most studies show that the incidence in both men and women is the same until the age of 80, when the incidence increases in women. Some studies show that the incidence is increased in women by up to a factor of 6. The major risk factors- Age, Sex, Genetics, and Hormone Deficiency.
Carriers of the Apolipoprotein E-e4 gene have an increased risk, as this gene results in less breakdown of Beta amyloid in the brain. In women, the negative effect is more pronounced.
Both estradiol and testosterone increase alpha secretase, an enzyme that prevents Beta amyloid formation; both also decrease Beta secretase, which decreases the formation of this “Darth Vader”. Estradiol and testosterone increase neprilysin, which degrades Beta amyloid. Testosterone and progesterone decrease hyperphosphorylation of tau proteins or the formation of tangles.
Testosterone is the major player, having a much greater effect than the other hormones.
Testosterone given alone to aging men and given with estradiol to postmenopausal women would probably prove beneficial in preventing and/or treating Alzheimer’s.
The National Academy of Sciences, in 2002,
If all that isn’t enough, testosterone and estradiol increase blood flow to the brain, help the brain use glucose for energy, and improve the function of neurotransmitters. When hormone levels are too low, our memory, cognition, focus, mathematical ability all decrease, resulting in “Brain Fog”.
Now remember back to our previous discussions on Bioidentical Hormones vs. Synthetic Hormones. Bioidentical hormones have the same exact chemical structure and 3D shape as the hormones we produce naturally. Bioidentical hormones can fit into their respective hormone receptors like a “key into a lock”. Synthetic hormones do not join receptors properly and tend to have negative effects. In the Women’s Health Initiative Memory Study (WHIMS), the risk of dementia increased by 105%! However the women in the study took Premarin (conjugated equine estrogens) and Provera (medroxyprogesterone acetate)! Provera, a synthetic progesterone, alone can block up to 95% of the testosterone receptors. Provera also contributes to cerebrovascular damage, inhibits the vasodilator effects of estrogen and has oxidant/cytotoxic effects on blood vessels! Premarin consists of mainly estrone, a type of estrogen known to increase the risk of Alzheimer’s. Oral estrogens and synthetic progesterones also increase the risk of thrombosis and stroke. Other large studies, including the Cache County Study and the Kaiser Study revealed that women who use oral/transdermal estrogen with or without synthetic progesterone within 5 years of menopause, had a decreased incidence of Alzheimer’s but if they used the same HRT later in menopause, the risk of Alzheimer’s increased by up to 48%. Because of the negative findings of these studies, largely using estrogens derived from horse urine and taken orally as well as synthetic progesterones, research on HRT and Alzheimer’s has unfortunately, rapidly declined.
Studies Related to Hormones & Alzheimer's
Low free testosterone levels increase the risk of Alzheimer’s (in men too). Multiple studies have shown that testosterone improves cognitive function in elderly women. The use of transdermal testosterone improves verbal learning and memory. Studies in female rodents have shown that testosterone with or without estradiol prevented the formation of “tangles”.
What about Men?
Men with early and late stages of Alzheimer’s disease have significantly lower levels of testosterone. Increased testosterone levels and testosterone therapy increase memory and cognition. A study by Dr. Lu concluded that testosterone therapy increased memory and quality of life in Alzheimer’s patients. Studies in male mice with low testosterone revealed increased Beta amyloid accumulation and behavioral impairment. Testosterone has also been shown to improve memory and cognition in a mouse model of Alzheimer’s disease.
Dr. Edward Friedman at the University of Chicago, and other researchers believe that we may prevent Alzheimer’s disease or even reverse early Alzheimer’s, with testosterone replacement in men and testosterone with or without estradiol/progesterone in women. It may be worthwhile to obtain his book, “How You and Your Doctor Can Fight Breast Cancer, Prostate Cancer and Alzheimer’s”. He has also recently published an excellent review “Hormones are the Answer to Alzheimer’s Disease” in 11/2018; 68 research studies are discussed!
References: E. Friedman, 2013; E. Friedman, 11/2018; C.Pike, Journal of Neuroscience, 2006; C. Pike, Journal of Neuroscience, 1/2017; L. Baum, Journal of Gerontology, 2005; P. Lu, Archives of Neurology, 2/2006; S. Papasozomenos, PNAS, 2002; S. Davis, Clinical Endocrinology, 10/2014; L. Chu, Journal Of Alzheimer’s Disease, 2010; H. Shao, Neurology, 2012; Alzheimer’s Association, Alzheimer’s Dementia, 3/2015; M. Mielke, Clinical Epidemiology, 2014
Dr. Cross graduated from Georgetown University School of Medicine in 1981. She completed her residency in Obstetrics and Gynecology at Naval Hospital San Diego in 1986 and received her board certification in Obstetrics and Gynecology in 1988, becoming a Fellow in the American College of Obstetrics and Gynecology in 1989. She is the Medical Director for Hormone Therapy of Citrus County and has also served as the Medical Director of Hormone Therapy Centers of America in Dallas, Texas. Dr. Cross continues to teach physicians across the country about Bioidentical Hormone Replacement.