Vitamin A

Is a fat soluble vitamin also known as Retinol or Retinal. Betacarotene is a precursor for this vitamin. It is important to maintain the health of the eyes and skin; for growth and tissue health, supports the immune system and the mucous membranes. Deficiency can result in night blindness, dry skin, infections and dandruff. Some natural sources are from fish oils, animal liver, egg yolk and butter.

Vitamin B1

Is a water soluble vitamin also known as Thiamine. It is important for a healthy nervous system, helps with irritability and fatigue, aids digestion, is vital for fat, protein and carbohydrate processing and also to maintain heart health. Deficiency can result in beri-beri, fatigue, confusion, constipation, muscle tenderness and insomnia, Some natural sources are from wheat germ, brown rice, pork, liver, brazil nuts, almonds, peanuts, brewers yeast, legumes and sunflower seeds.

Vitamin B2

Is a water soluble vitamin also known as Riboflavine. It is important for skin, eye and hair health, aids digestion, is necessary for energy production and normal cell growth and activates vitamin B6 and folic acid. Deficiency can lead to soreness and redness of the tongue, eye fatigue, dermatitis, hair loss and low vitality. Some natural sources are from brewer's yeast, mushrooms, wheat germ, liver, yoghurt, millet, avocado, eggs, sardines, split peas and almonds.

Vitamin B3

Is a water soluble vitamin also known as Niacin or Niacinamide. It is important for carbohydrate, fat and protein metabolism, releasing energy from food, for healthy skin, nerve support and maintaining hydrochloric acid production. Deficiency can result in pellagra, thickening and dryness of the skin, low stomach acidity, burning mouth and insomnia. Some natural sources are from brewer's yeast, cod, mackerel, brown rice, beef, almonds, chicken, peanuts, sunflower seeds and peas.

Vitamin B5

Is a water soluble vitamin also known as Pantothenic Acid. It is important to maintain adrenal function and the nervous system, it may also ease stiffness in arthritis, helps to relieve fatigue and stimulates gut peristalsis.. Deficiency can result in fatigue, abdominal cramps, skin problems, burning feet and stress. Some natural sources are from brewer's yeast, liver, wheat germ, brown rice, split peas, chicken, mushrooms, peanuts, broccoli, eggs.

Vitamin B6

Is a water soluble vitamin also known as Pyridoxine. It is important to maintain the nervous system and immune function; is helpful for premenstrual symptoms, helps with morning sickness and fluid retention and supports carbohydrate metabolism. Deficiency can result in muscle weakness, irritability, fatigue, poor immunity, acne and nausea. Some natural sources are from liver, lamb, beef, clams, egg yolk, mackerel, sardines, trout, tuna, salmon, milk, seaweed and brewer's yeast.

Vitamin B12

Is a water soluble vitamin also known as Cyanocobalamin. It is vital for healthy red blood cell production, cardiovascular and nervous systems and can improve memory.
Deficiency can lead to pernicious anaemia, mood changes, numbness, irritability and fatigue. Vegetarians may be deficient in B12. Some natural sources are from liver, lamb, beef, clams, egg yolk, makerel, sardines, trot, tuna, salmon, milk, seaweed and brewer's yeast.

Betacarotene

Is a fat soluble precursor to vitamin A and part of the carotenoid family. It is an important antioxidant, important for healthy eyes, immune system, protects the skin and accelerates wound healing. Deficiency can lead to infections, poor eye health and poor antioxidant status. Some natural souces are from carrots, sweet potato, red capsicum, paw-paws, mangos, spinach, pumpkin, broccoli, parsley and apricots.

Biotin

Is a water soluble vitamin also known as Vitamin B7 or Vitamin H. It is important for Healthy hair, skin and nails, digestive function, cell growth, metabolism of fat, protein and carbohydrate. Deficiency can lead to an fatigue, dry flaky skin, hair loss, inflamed eyes and muscle weakness. Some natural sources are from brewer's yeast, liver, barley, oatmeal, egg yolk, soybeans, split peas, brown rice, mushrooms and pecans.

Vitamin C

Is a water soluble vitamin also known as Ascorbic acid. It is important for the formation of collagen and connective tissue, as an antioxidant, immune system support, improves iron absorption and assists in wound healing. Deficiency can lead to scurvy, infections, easy bruising, bleeding gums and joint pain. Some natural sources are from guavas, blackcurrants, red capsicun, strawberries, oranges, broccoli, paw-paws, mangos, carrots and kiwi fruit.

Vitamin D

Is a fat soluble vitamin also known as Cholecalciferol. It is important for strong, healthy bones and teeth, aids calcium absorption; regulates the body's use of calcium and phosphorus and helps to prevent rickets. Deficiency can result in the softening of bones and teeth, rickets, poor growth and muscle spasms. Some natural sources are from cod liver oil, halibut liver oil, salmon, tuna, liver, egg yolk, butter, cheese and cream.

Vitamin E

Is a fat soluble vitamin also known as tocopherol. It is important for healthy arteries, heart and tissue function, circulation, reduction of scar tissue, antioxidant and immune function support. Deficiency can result in a decline in red cell count, fatty deposits, muscle wasting and infections. Some natural sources are from wheat germ oil, soybean oil, sunflower oil, sunflower seeds, wheat germ, peanuts, eggs and avocado.

Folic acid (see also Folinic acid below)

Is a water soluble co factor also known as folate and Folacin. It helps to reduce birth defects such as spina bifida and other neural tube defects if taken during pregnancy, it promotes good cardiovascular health and assists to normalise homocysteine levels, which at high levels can lead to cardiovascular disease. Deficiency can lead to anaemia, heart palpitations, fatigue, poor memory and cracked lips. Some natural sources are from brewer's yeast, wheat germ, wheat bran, rye, kidney beans, chic peas, lentils, liver, spinach, broccoli and cabbage.

Folinic acid
Folinic acid, also known as 5-formyl tetrahydrofolate, is one active form in a group of vitamins known as folates. In contrast to folic acid, a synthetic form of folate, folinic acid is one of the forms of folate found naturally in foods. Folate deficiency is believed to be the most common vitamin deficiency in the world due to food processing, food selection, and intestinal disorders. In the body folinic acid may be converted into any of the other active forms of folate. Folate coenzymes are responsible for the following important metabolic functions:
1) Formation of purines and pyrimidines which, in turn, are needed for synthesis of the nucleic acids DNA and RNA. This is especially important during fetal development in the first trimester in preventing birth defects, such as neural tube defects,
2) Formation of heme, the iron-containing protein in hemoglobin,
3) Interconversion of the 3-carbon amino acid serine from the 2-carbon amino acid glycine,
4) Formation of the amino acids tyrosine from phenylalanine and glutamic acid from histidine,
5) Formation of the amino acid methionine from homocysteine (Vitamin B12 as methylcobalamin also is needed for this conversion). Elevated levels of homocysteine have been implicated in a wide range of health disorders including atherosclerosis, osteoporosis, Alzheimer's disease, and depression. In the reconversion of homocysteine to methionine the body uses the methionine to make the important amino acid s-adenosylmethionine (SAMe) which is known to be helpful in cases of depression,
6) Synthesis of choline from ethanolamine,
7) Formation and maturation of red and white blood cells, and
8) Conversion of nicotinamide to N'-methylnicotinamide. Other conditions than those mentioned above possibly benefiting from folinic acid supplementation include: AIDS/HIV, celiac disease, cervical displasia, cleft palate, colon cancer, Crohn's disease, diarrhea, gout, high cholesterol, increased fracture of chromosomes, malabsorption and gastrointestinal inflammation, megaloblastic anemia, restless leg syndrome, postpartum depression, sprue, ulcerative colitis, and vitiligo.
Numerous drugs are known to inhibit the body's ability to utilize folate, including: 1) aspirin,
2) cholesterol lowering drugs,
3) oral birth control pills
4) antacids and
5) methotrexate when used for rheumatoid arthritis. When taking these drugs (and many others) it is recommended that you take 800 mcg daily of folate, preferably as folinic acid. When taking folate it is recommended that you take adequate amounts of Vitamin B12 as methylcobalamin. Please note that folate supplementation may interfere with anticonvulsant drugs.

Vitamin K

Is a fat soluble vitamin also known as Phytomenadione. It is required for proper bone formation, helps with the transportation of calcium and is important for blood clotting.. Deficiency can lead to nose blleds, birth defects, bone abnormalities, hemorrhagic disorders and increased propensity for bruising. Some important sources are parsley, brussels sprouts, green tea, liver, spinach, cabbage, tomatoes, string beans, lettuce and eggs.

Introduction

Sometimes called the "king of hormones", testosterone is certainly the most important hormone when it comes to sexual characteristics in men. The group of hormones that create and support masculinity is known as the androgens, but testosterone is the androgen that is primarily responsible for:

• Determining before birth whether a baby will develop into a boy or a girl
• Influencing sexual preferences.
• Forming personalities into poets, athletes, competitors or co-operators.
• Regulating the sex drive in men (and in women, but in far lower amounts than men).
• Starting and maintaining the development of male sexual characteristics including dominance, emotional and physical strength, body shape, hairiness, deep voice, and even odour.
• Governing sperm production and quality.
• The ability to perform adequately during sexual intercourse.

Testosterone plays a role in developing creativity, intellect, thought patterns, assertiveness and drive, as well as the ability to propose new ideas and carry them through to successful conclusions. It also affects general health during childhood, adolescence and adulthood. Adequate levels of testosterone throughout life help males to thrive as children, develop stronger muscles and bones (along with acne) during puberty, cope with stress during peak career years, and age gracefully after retirement.

Production in the Body

This important hormone is produced mainly in the testes in males (more than 95 percent) and in the ovaries in females; however, small amounts are made in the outer layer of the adrenal glands in both sexes. The process that carefully regulates the amount and timing of testosterone production is complex and begins in the brain. When a man feels aroused or successful, the cerebral cortex, the most sophisticated area of the brain, sends a signal to another part of the brain called the hypothalamus to stimulate the production of testosterone. The hypothalamus is an area at the base of the brain that regulates much of the body's hormonal activity. It does this by sending chemical signals to the pituitary gland, a cherry-sized organ that produces a wide variety of hormones involved in the regulation of growth, thyroid function, blood pressure, pregnancy, birth and other critical body functions.

To stimulate testosterone production, the hypothalamus releases a substance to the pituitary gland called gonadotropin-releasing hormone (GnRH). This hormone, in turn, causes the gland to produce two other hormones, follicle-stimulating hormone (FSH) and luteinising hormone (LH), collectively known as gonadotropins. LH is released into the bloodstream where it travels to the testes and triggers the production of testosterone from cholesterol. If this process continues until the testosterone level becomes too high, the pituitary slows the release of LH so production slows down. FSH is similarly involved in the increase and decrease in sperm production.

When LH reaches the testes, it influences activity in the Leydig cells, which are where cholesterol is gradually changed into a series of compounds until it becomes testosterone. When the small but vital amount of testosterone produced is released into the bloodstream, it is mostly bound to a special "carrier" compound called sex hormone binding globulin or SHBG, which is produced by the liver, and plays an important role in regulating the amount of "free" testosterone circulating in the body at any one time. The more SHBG there is the less unbound, active testosterone is able to move from the blood stream into cells where it is needed. As SHBG levels rise and fall, so do free testosterone levels, except in reverse.

With such a complex chain of events leading to a normal testosterone level, many problems or interruptions along the process can lead to sub-normal levels in men at any age. If there are diseases or negative conditions involving the testes, hypothalamus, pituitary gland or genetic material, the resulting state is called hypogonadism.

A variety of conditions can cause low testosterone besides aging:

• The testicles may be damaged, especially the Leydig cells, during sports or from other physical trauma.
• A case of mumps after puberty can cause an inflammation of the testes that interferes with testosterone and sperm production.
• Radiation treatment or chemotherapy can have a negative effect on the Leydig cells.
• Testicular or pituitary tumours can also have an impact on the testosterone level.
• HIV/AIDS and other serious viral infections can inflict damage on the pituitary gland, the hypothalamus or the testes.
• Genetic conditions such as Klinefelter's, Kallmann's and Prader-Willi syndromes and myotonic dystrophy all can have a negative impact on testosterone production.
• Vasectomy may damage the Leydig cells and lead to early andropause.

In addition, many lifestyle habits affect the way testosterone is produced. A diet high in meat and poultry may expose a man to hormones used in meat production that act like estrogen in the body. Estrogen is a potent inhibitor of testosterone production as are prolonged periods of high stress. Mild to moderately intense physical stress, as in casual sports and sexual intercourse, may actually boost testosterone production. Alcohol consumption, on the other hand, has been proven to have a strong negative impact on testosterone levels. Beer, which contains plant estrogens, is particularly toxic to the testes. Excessive beer consumption can lead to gynecomastia (breast development). As we all know, the testes are very heat sensitive so switching from jockey shorts and tight jeans to boxers and loose pants may raise the testosterone level.

Age-related changes to testosterone level

It is helpful to define andropause in terms that relate to lowered testosterone levels in men regardless of age. One doctor in a recent journal defined it as "a decline in serum (blood) testosterone in older men to levels below the normal range for young men, with associated clinical manifestations consistent with androgen deficiency."¹

Aging in men is associated with a one percent decline in total testosterone level each year starting at around age forty. About twenty percent of men in their sixties and fifty percent of men in their eighties have testosterone levels significantly below normal. Men who develop a serious illness, take certain kinds of medications, or who don't eat a healthy variety of foods are even more likely to have low testosterone levels. Furthermore, about one in three men with symptoms of andropause turn out to have a testosterone level lower than normal². Many of these men will simply feel better when their testosterone level is raised through hormone replacement therapy.

The relationship between testosterone and SHBG has confused many who question the existence of andropause as a legitimate syndrome. They have argued that the level of total testosterone as measured in blood falls only slightly up to the age of 70. This is true. Yet, the level of SHBG tends to increase with aging. At any time, approximately 98 percent of circulating testosterone is bound to SHBG, which leaves only 1-2 percent available for use by cells. If SHBG levels increase with age while testosterone production decreases, the amount of available testosterone is actually decreasing at a faster rate than total testosterone.

The age-related decline in testosterone production is due to many factors that produce a gradual downward spiral:

• The number of Leydig cells declines.
• The existing Leydig cells produce less testosterone.
• Less testosterone is secreted into the bloodstream by the testes in response to LH.
• The hypothalamus secretes less gonadotropin-releasing hormone.
• As a result, production of LH by the pituitary gland decreases and less testosterone production is demanded of the testes.

Aging also may change the daily cycle of testosterone production. In young men, peak testosterone delivery occurs in the morning, as evidenced by morning erections when testosterone levels are highest. As men age, the testosterone level becomes increasingly more constant throughout the day and night. As men age testosterone levels often fall off dramatically in the early afternoon leading to excessive tiredness.

This simplified view of age-related changes to testosterone levels leads to questions about the actual effects the decreasing level has on the body, mind and emotions of the aging male. By no means does the decline in testosterone account for all of these changes but it certainly plays a significant role.

Physical symptoms of low testosterone include:

• Poor or no erections
• Decline in sexual activity
• Loss of muscle mass and strength
• Loss of bone mass that can lead to osteoporosis
• Fatigue and loss of energy
• Reduction in body hair and skin thickness
• Development of hair in ears and nose
• Increase in upper and central body fat
• Increase in heart and artery disease
• Problems with circulation
• Sleep disturbances

Mental symptoms include:

• Decreased intellectual ability
• Memory loss

Emotional symptoms include:

• Loss of interest in sex
• Depression
• Irritability
• Loss of sense of well-being

Each individual may experience a different number and type of symptoms. Some symptoms may be clearly related to other physical and mental illnesses or even to such poor habits as smoking, drinking too much alcohol or overeating. Before assuming that testosterone supplementation is necessary to feel better, you and your doctor will want to run through a variety of diagnostic steps to pinpoint specific causes of your symptoms and a full range of behavioural and other changes that might help you feel better.

References

1. Matsumoto, Alvin M. Fundamental Aspects of Hypogonadism in the Aging Male. Urology. Vol. 5, Supplement 1. 2003; S3-10.

2. Morley, JE. J Gend Specif Med. 2001;4:49-53.