Zinc
Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement. Zinc is involved in numerous aspects of cellular metabolism. Zinc is involved in numerous aspects of cellular metabolism. It is required for the catalytic activity of approximately 100 enzymes and it plays a role in immune function, protein synthesis, wound healing, DNA synthesis and cell division. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence and is required for proper sense of taste and smell. Zinc is critical for men as it boosts testosterone (the formation of estrogen from testosterone increases if men are zinc deficient).
Consume plenty of Zinc. Zinc reduces the frequency of illness and supports optimal levels of testosterone. In high doses, zinc can act as an aromatase inhibitor and reduce estrogen levels. It is also a potent antioxidant and can provide benefits for prostate issues. Zinc is lost through sweating, so you need to get a lot of zinc through correct foods.
Zinc benefits hormonal health and fertility because it plays an important role in hormone production, including increasing testosterone naturally. Zinc also impacts female sex hormones and is even involved in the creation and release of eggs within and from the ovaries. Zinc is needed for the production of estrogen and progesterone in women. Either too high or too low levels of estrogens can cause problems with menstruation, mood swings, early menopause, infertility and possibly even increase the risk for certain cancers.
Zinc + vitamin B6 + magnesium combo
Taking these 3 micro-nutrients has been proven to increase testosterone levels. These are often sold as a supplement called ZMA which is popular with body builder and athletes. A typical ZMA supplement contains 10mg of B6, 30mg zinc and 400-500mg of magnesium. But taking ZMA is a waste of time if you compare it to a good multi-vitamin and eating some B6 and zinc rich foods.
Oysters, beef, crab, Lamb, pumpkin seeds, beef patty, lobster and dark chocolate seem to come out on top in zinc intake. Alcohol consumption decreases intestinal absorption of zinc and increases zinc excretion via urine. Eating foods rich in iron also decreases zinc absorption. Because of the importance of zinc for men (testosterone production), we would recommend using a zinc supplement (unless you are a serious oyster eater!). Zinc supplement typically come in at 15mg/tablet or capsule. Centrum for adults, a multivitamin, contains 11mg. There are some long term effects of very high zinc consumption (40mg/day is the upper tolerable limit and the UK food agency say zinc should not exceed 25mg/day).
The phytate problem
Epidemiological data suggest at least one in five people are at risk of zinc deficiency. This is in large part because the phytate in seeds, wholegrains, nuts and cereals. The phytates bind with zinc to prevent it's absorption (plants use this to hang on to their zinc). Sunflower seeds have lots of zinc but also lots of phytate, so a vegetarian approach to getting enough zinc is sometimes difficult.
Zinc supplementation
If you are eating a zinc rich diet, there still may be a need to take a zinc supplement. We would recommend no more that 10-15mg per day, as you will also be getting some from food. The upper tolerable limit for zinc is 40mg so only take 1 capsule/tablet. Copper and zinc have an interesting relationship, as one of these elements causes the other element to decrease in your body. So the ideal supplement would be zinc + copper. (Centrum for men contains 11mg zinc and 0.9mg copper, this is 100% RDA for copper). Roughly 2mg of copper should be consumed for every 15mg of zinc.
RDA Children:
- 1–3 years: 3 milligrams/day
- 4–8 years: 5 milligrams/day
- 9 –13 years: 8 milligrams/day
RDA Adolescents and adults:
- Males age 14 and over: 11 milligrams/day
- Females age 14 to 18 years: 9 milligrams/day
- Females age 19 and over: 8 milligrams/day
(more zinc is required if you exercise a lot, ejaculate a lot, are pregnant, have an injury or are breastfeeding. If you are diabetic or drink a lot you will excrete more zinc)
Zinc Deficiency
Zinc deficiency is characterised by growth retardation, loss of appetite and impaired immune function. In more severe cases, zinc deficiency causes hair loss, diarrhea, delayed sexual maturation, impotence, hypogonadism in males and eye and skin lesions. Weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy can also occur.
Age-related macular degeneration
Researchers have suggested that both zinc and antioxidants delay the progression of age-related macular degeneration (AMD) and vision loss, possibly by preventing cellular damage in the retina
Selected Food Sources of Zinc
| Food | Milligrams (mg) per serving |
RDA |
|---|---|---|
| Oyster, 1 medium | 9 | 60% |
| Beef, 3 ounces | 7.0 | 47% |
| Crab, Alaska king, cooked, 3 ounces | 6.5 | 43% |
| Lamb, 100g | 6.5 | 43% |
| Pumpkin seeds, 2 ounces (54g) | 5.8 | 38% |
| Beef patty, broiled, 3 ounces | 5.3 | 35% |
| Breakfast cereal, fortified, ¾ cup serving | 3.8 | 25% |
| Lobster, cooked, 3 ounces | 3.4 | 23% |
| Dark chocolate, 100g | 3.3 | 23% |
| Pork chop, loin, cooked, 3 ounces | 2.9 | 19% |
| Baked beans, canned, plain or vegetarian, ½ cup | 2.9 | 19% |
| Chicken, dark meat, cooked, 3 ounces | 2.4 | 16% |
| Yogurt, fruit, low fat, 8 ounces | 1.7 | 11% |
| Cashews, dry roasted, 1 ounce | 1.6 | 11% |
| Chickpeas, cooked, ½ cup | 1.3 | 9% |
| Cheese, Swiss, 1 ounce | 1.2 | 8% |
| Oatmeal, 1 packet | 1.1 | 7% |
| Milk, low-fat or non fat, 1 cup | 1.0 | 7% |
| Almonds, dry roasted, 1 ounce | 0.9 | 6% |
| Kidney beans, cooked, ½ cup | 0.9 | 6% |
| Chicken breast, ½ breast | 0.9 | 6% |
| Cheese, cheddar or mozzarella, 1 ounce | 0.9 | 6% |
| Peas, green, frozen, cooked, ½ cup | 0.5 | 3% |
| Flounder or sole, cooked, 3 ounces | 0.3 | 2% |
Zinc intake strategy
Our advice is to take a zinc supplement or a multivitamin, just to ensure you are getting enough. Oysters are the star when it comes to zinc, so if you have one or two portions a week you are doing well. Eat lots of quality beef, crab, lamb and pumpkin seeds as a snack.
Adequate intake: 11mg per day for men and 9mg for women.
Theraputic dose: 15mg (If you sweat a lot you need a little more).
Upper tolerable limit: 40mg.
Notes: Ensure you have plenty of magnesium, copper and vitamin B6 in your diet.
Sources: draxe.com, drmercola.com, ods.od.nih.gov, nhs.uk