Can we prevent aging ? Part 2

Testosterone
Testosterone is a vital sex hormone that plays an important role in puberty. In men, testosterone not only regulates sex drive (libido), it also helps regulate bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm. Testosterone isn’t exclusively a male hormone—women produce small amounts as well.
As men age, they often produce somewhat less testosterone, especially compared to years of peak testosterone production during adolescence and early adulthood. Normal testosterone production ranges widely, and it is unclear what amount of decline or how low a level of testosterone will cause adverse effects.
In recent years, the popular press has increasingly reported about “male menopause,” a condition supposedly caused by diminishing testosterone levels in aging men. There is very little scientific evidence that this condition, also known as andropause or viropause, exists. The likelihood that an aging man will experience a major shutdown of testosterone production similar to a woman’s menopause is very remote. In fact, many of the changes that take place in older men often are incorrectly attributed to decreasing testosterone levels. For instance, some men experiencing erectile difficulty (impotence) may be tempted to blame it on lowered testosterone, but many cases of erectile problems are due to circulatory problems.
For men whose bodies make very little or no testosterone, testosterone replacement may offer benefits. FDA-approved testosterone drugs come in different forms, including patches, injections, and topical gels. Men whose testes (the reproductive glands that make testosterone and sperm) have been damaged or whose pituitary glands have been harmed or destroyed by trauma, infections, or tumors may also be prescribed testosterone. Treatment with testosterone drugs can help men with exceptionally low testosterone levels maintain strong muscles and bones and increase their sex drive. It is unclear if men who are at the lower end of the normal range for testosterone production would benefit from treatment.
More research is needed to learn what effects testosterone drug therapy may have in healthy older men without these extreme deficiencies. NIA is investigating the role of testosterone therapy in delaying or preventing frailty and helping with other age-related health issues. Results from preliminary studies involving small groups of men are inconclusive. Specifically, it remains unclear to what degree testosterone supplements can help men maintain strong muscles and sturdy bones, sustain robust sexual activity, or sharpen memory.
There are also concerns about the long-term, harmful effects that testosterone drugs might have on the aging body. Most epidemiological studies suggest that higher natural levels of testosterone are not associated with a higher incidence of prostate cancer—the second leading cause of cancer death among men. However, scientists do not know if taking testosterone drugs increases men’s risk for developing prostate cancer or promoting the growth of an existing tumor. There is also uncertainty about effects of testosterone treatment on the cardiovascular system in older men, especially men with mobility limitations and other diseases. Future studies will address this issue to ensure that older men receiving testosterone treatment are not exposed to unnecessary risks.
The bottom line: there is no scientific proof that testosterone treatment in healthy men will help them age better. Until more scientifically rigorous studies are conducted, it is not known if the possible benefits of testosterone therapy outweigh any of its potential risks. NIA continues to conduct research to gather more evidence about the effects of testosterone treatment in aging men.


Hormones in Women

Estrogen and progesterone are two hormones that play an important part in women’s menstrual cycle and pregnancy. Estrogen also helps maintain bone strength and may reduce the risk of heart disease and memory problems before menopause. Both estrogen and progesterone are produced naturally by the ovaries. However, after menopause, the ovaries make much less of these hormones. For more than 60 years, millions of women have used estrogen to relieve their menopausal symptoms, especially hot flashes and vaginal dryness. Some women may also be prescribed estrogen to prevent or treat osteoporosis—loss of bone strength—that often happens after menopause. The use of estrogen (by a woman whose uterus has been removed) or estrogen with progesterone or a progestin, a synthetic form of progesterone (by a woman with a uterus), to treat the symptoms of menopause is called menopausal hormone therapy (MHT), formerly known as hormone replacement therapy (HRT).
There is a rich research base investigating estrogen. Many large, reliable long-term studies of estrogen and its effects on the body have been conducted. Yet, much remains unknown. In fact, the history of estrogen research demonstrates why it is important to examine both the benefits and risks of any hormone therapy before it becomes widely used. Here’s what scientists know:

-          Endometrial problems—While estrogen helps some women with symptom management during and after menopause, it can raise the risk of certain problems. Estrogen may cause a thickening of the lining of the uterus (endometrium) and increase the risk of endometrial cancer. To lessen these risks, doctors now prescribe progesterone or a progestin, in combination with estrogen, to women with a uterus to protect the lining.

-          Heart disease—The role of estrogen in heart disease is complex. Early studies suggested MHT could lower postmenopausal women’s risk for heart disease—the number one killer of women in the United States. But results from the NIH Women’s Health Initiative (WHI) suggest that using estrogen with or without a progestin after menopause does not protect women from heart disease and may even increase their risk.
In 2002, WHI scientists reported that using estrogen plus progestin actually elevates some postmenopausal women’s chance of developing heart disease, stroke, blood clots, and breast cancer, but women also experienced fewer hip fractures and cases of colorectal cancer. In 2004, WHI scientists published another report, this time on postmenopausal women who used estrogen alone, which had some similar findings: women had an increased risk of stroke and blood clots, but fewer hip fractures. Then, in 2007, a closer analysis of the WHI results indicated that younger women, ages 50 to 59 at the start of the trial, who used estrogen alone, had significantly less calcified plaque in their coronary arteries than women not using estrogen. Increased plaque in coronary arteries is a risk factor for heart attacks. Scientists also noted that the risk of heart attack increased in women who started MHT more than 10 years after menopause (especially if these women had menopausal symptoms). There was no evidence of increased risk of heart attack in women who began MHT within 10 years of going through menopause.

-          Dementia—Some observational studies have suggested that estrogen may protect against Alzheimer’s disease. However, testing in clinical trials in older, postmenopausal women has challenged that view. In 2003, researchers leading the WHI Memory Study (WHIMS), a substudy of the WHI, reported that women age 65 and older who took one kind of estrogen combined with progestin were at twice the risk for developing dementia compared to women who did not take any hormones. In 2004, WHIMS scientists reported that using the same kind of estrogen alone also increased the risk of developing dementia in women age 65 and older compared to women not taking any hormones. What possibly accounts for the different findings between the observational and clinical studies? One central issue may be timing. The women in the WHIMS trial started treatment a decade or more after menopause. In observational studies that reported estrogen’s positive effects on cognition, the majority of women began treatment soon after menopause. This has led researchers to wonder if it may be advantageous to begin treatment earlier, at a time closer to menopause. Additionally, it appears that progesterone and progestins (progesterone-like compounds) differ in their impact on brain health.
Despite research thus far, there are still many unknowns about the risks and benefits of MHT. For instance, because women in their early 50’s were only a small part of the WHI, scientists do not yet know if certain risks are applicable to younger women who use estrogen to relieve their symptoms during the menopausal transition.
You may also have heard about another approach to hormone therapy for women—“bioidentical hormones.” These are hormones derived from plants, such as soy or yams, that have identical chemical structures to hormones produced by the human body. The term “bioidentical hormones” is now also being applied to the use of compounded hormones. Large clinical trials of these compounded hormones have not been done, and many bioidentical hormones that are available without a prescription are not regulated or approved for safety and efficacy by the FDA. FDA-regulated bioidentical hormones, such as estradiol and progesterone, are available by prescription for women considering MHT.
For middle-age and older women, the decision to take hormones is far more complex and difficult than ever before. Questions about MHT remain. Would using a different estrogen and/or progestin or different dose change the risks? Would the results be different if the hormones were given as a patch or cream, rather than a pill? Would taking progestin less often be as effective and safe? Does starting MHT around the time of menopause, compared to years later, change the risks? Can we predict which women will benefit or be harmed by using MHT? As these and other questions are addressed by research, women should continue to review the pros and cons of MHT with their doctors. They should assess the benefits as well as personal risks to make an informed decision about whether or not this therapy is right for them.


DHEA

Dehydroepiandrosterone, or DHEA, is made from cholesterol by the adrenal glands, which sit on top of each kidney. It is converted by the body into two other important hormones: testosterone and estrogen.
For most people, DHEA production peaks in the mid-20’s and then gradually declines with age. The effects of this decline, including its role in the aging process, are unclear. Even so, some proponents claim that over-the-counter DHEA supplements can improve energy and strength and boost immunity. Claims are also made that supplements increase muscle and decrease fat. To date, there is no conclusive scientific evidence that DHEA supplements have any of these benefits.
The conversion of naturally produced DHEA into estrogen and testosterone is highly individualized. There is no way to predict who will make more or less of these hormones. Having an excess of testosterone or estrogen in your body could be risky.
Scientists do not yet know the effects of long-term (defined as over 1 year) use of DHEA supplements. Early indications are that these supplements, even when taken briefly, may have detrimental effects on the body, including liver damage. But the picture is not clear. Two short-term studies showed that taking DHEA supplements has no harmful effects on blood, prostate, or liver function. However, these studies were too small to lead to broader conclusions about the safety or efficacy of DHEA supplementation.
Researchers are working to find more definite answers about DHEA’s effects on aging, muscles, and the immune system. In the meantime, if you are thinking about taking DHEA supplements, be aware that the effects are not fully known and might turn out to cause more harm than good.
Source: https://www.nia.nih.gov/health/publication/can-we-prevent-aging