There has been a lot of talk recently about anti-ageing. We must first look at what exactly is ageing and how can we control it? I suppose as a Molecular Biologist and Doctor I must say that ageing is really an accumulation of damage to molecules, cells, tissue and eventually organs. The maximum life span known for humans is 122 years, whereas the maximum lifespan of a mouse is about 3 years. There are many reasons this happens, genetic differences between humans and mice, fertility rate, efficiency of DNA repair and the old "buzzword" different rates of free radical production, etc. Antioxidants, including Vitamins A, B-6, B-12, C and E are believed to counteract free radicals and in some way prevent chronic disease such as heart disease and diabetes. There are many studies that point towards the benefits of beta-carotene, folic acid and selenium. These anti-oxidants are found in a variety of fruits and vegetables. I suppose as a scientist, I am cynical about the advantage of these adjuncts in pill form.
Regarding hormone use, I am going to stand out on a limb and look at the evidence supporting their use. When people talk about hormones, they usually mean taking DHEA, Testosterone, Oestrogen and probably Human Growth Hormone. Hormones are chemicals needed to help keep your vital organs working properly, which decline naturally as we age. It is easy to see why people would believe restoring their level to lead to previous levels. Unfortunately, life is never that simple. We all know that HRT can restore a woman's skin, vaginal secretions, energy etc. but it has its risks in older age groups also. Look at the precursor hormone DHEA, which is converted in the body to oestrogen and testosterone. DHEA has long been touted as an anti-ageing therapy, used to ward off chronic illness and maintain energy and vigour. Proponents say it also slows ageing, increases muscle and bone strength, burns fat, improves cognition and bolsters immunity. However, an October 2006 study published in the New England Journal of Medicine by Sreekumaran Nair, M.D., an endocrinologist at Mayo Clinic, Rochester, found no evidence that taking DHEA reverses the effects of ageing.
DHEA is the most abundant naturally occurring hormone circulating in the human body. It is secreted by the adrenal glands and reaches its peak by the early twenties and then declines with age. The decline with age of DHEA levels correlates with many age-related changes, including peaking at games, of muscle mass, of bone density, physical endurance and ability to fight disease. The study showed no significant beneficial effects on any of those factors in men and women in their 60s and 70s. I don't mind standing out on a limb on some issues but not this one as I don't really know. I expect not as its use is regulated by the FDA in the United States. This hormone is extensively promoted and used as an anti-ageing nutrient supplement by people hoping it will restore the pleasure of youth or increase longevity. I expect, science does not support its use, although I am sure there are many people who would disagree with me on this one. The increasing use of testosterone is also one to watch. The male menopause, does it really exist? We do know for many years that declining levels of testosterone have been linked with decreased energy and sex drive, decreased muscle mass, decreased mental ability and even osteoporosis. We also know that more and more men are taking testosterone but not enough is known about the long term effects of testosterone therapy for this purpose.
In essence, doctors feel uncomfortable about prescribing this hormone because of the lack of scientific evidence to balance whether the declining levels are unhealthy, especially as there is suspicion towards possible risks, including prostate problems. We do know that about 20% of men age 60 and older have testosterone levels below the normal range (testosterone deficiency). The question is shouldn't these men be treated? In a sentence I would agree. If a patient feels decreased energy, reduced strength or cognitive ability, less sexual interest or potency, I would certainly check his testosterone levels as well as his thyroid levels, mood and medication. If his testosterone proved to be low I would treat him. In men with testosterone deficiency, testosterone therapy can restore sexual function and protect against heart disease (atherosclerosis). Also, some men taking testosterone therapy report an increase in energy, sex drive and well-being. In effect, I would not deprive patient of testosterone if he was aware of the potential benefits and risks of the medication. Though potentially beneficial, high doses of testosterone may result in sleep apnea, infertility and it may also pose problems for prostate and breast cancer in men. Probably, patients with a family history of prostate or breast cancer should be cautioned. It can be taken in tablet form but many doctors say, that testosterone taken by this method may cause an unfavourable cholesterol profile thereby increasing the risk of blood clots and heart and liver problems. Several other types of testosterone therapy exist. Intramuscular testosterone injections (Delatestryl, Depo-Testosterone) are safe and effective. Injections are given approximately every two weeks. A patch containing testosterone (Androderm) is applied each night to your back, abdomen, upper arm or thigh. The site of the application is rotated to maintain seven-day intervals between applications to the same site to lessen skin reactions. In Ireland, your GP can prescribe a testosterone gel (TestoGel) to put on the skin of the lower abdomen, upper arm or shoulder. I think it also comes in a chewing gum form.
Many patients ask me about my attitudes regarding the increasing use of Growth Hormone, I suppose my early tempered memories are prejudiced because of my time working as a young doctor in Our Lady's Children's Hospital in Dublin the late eighties when the news surfaced that the cadaver growth hormone they had been using was implicated in multiple cases of Creutzfeldt-Jakob disease (CJD). This spurned an interest in limb lengthening procedures in our Orthopaedic Department. The medicine was also used for children with kidney disease, Turner's syndrome, Prader-Willi syndrome and muscle wasting associated with AIDS and HIV. We knew that growth hormone caused growth in childhood and helped maintain tissue throughout our life. We also know the level of growth hormone in our bodies begins to drop during mid life. in our 40s. Studies of adults with growth hormone deficiencies show that injections of growth hormone can: increase bone density, increase muscle mass, decrease body fat, improve mood and motivation and increase exercise capacity. It's not hard to see why people believe that synthetic growth hormone could help healthy older adults who have naturally low levels of growth hormone regain some of their youth and vitality. We do not have a lot of clinical data but most studies show that Growth Hormone injections can increase muscle mass and reduce the amount of body fat in healthy older adults. It was not exactly clear whether they became stronger or had increased mood. The studies pointed towards a number of side effects, including: swelling in the arms and legs, arthritis-like symptoms, carpal tunnel symptoms, headaches, muscle pain and worse still unfortunately diabetes, hardening of the arteries and high blood pressure.
Many patients also ask me whether hormones will restore the vitality of youth. I really hate to sound like a kill joy, especially as I am continually asked to speak at anti ageing conferences and I realise that this part of medicine is in its infancy. I am also aware that the new science of nutrigenomics will become more important. In essence, I would really love to see a hormonal answer to stop the process of ageing but none of these supplements has sufficient medical evidence to back up the claims made by anti-ageing enthusiasts in view of the risks they carry. We all know that post menopausal hormone replacement therapy also carries significant risks, including breast cancer and an increased risk of blood clots leading to heart disease and heart attack. However, unlike the other hormones it has been the subject of extensive research and I have prescribed it for many years and valued its benefit in treating mental alertness, hot flushes, vaginal dryness and poor skin. The real fifty dollar question is whether calorie restriction theory really applies to humans. I believe that the theory is based on studies in animals, including rats, mice, fish, flies and worms. These studies found that the life span of each species could be extended by reducing the number of calories consumed. Clinical trials in humans tend to show that underweight people are more susceptible to disease and death. We would have to make sure that calorie-restricted diets were still rich in fruits and vegetables so that dieters still get the nutrients they need.
To finish, I really think that ageing is a more complex process than presently perceived. It involves many aspects of tissue function, most importantly genetic make up and it's as yet unlikely that a pharmaceutical product can cure many of the ills age can bring. That is not to say, we should not continue to chase the elixir of youth. I suspect things such as heavy exercise in later years may actually increase free oxide radicals and shorten life. Any A&E Officer will tell you about the number of myocardial infarctions brought in from badminton games, tennis games or even golf courses. Others say that's just what people do in retirement. That is not to say controlled exercise is of course beneficial for cardiac disease. Your best bet for a long and healthy life is to have the right parents, eating plenty of fruits and vegetables, maintain a healthy weight, exercise a little every day, don't smoke, use sunscreen and laugh a lot...I suppose all the things that I don't do!