Many in the Paleosphere are familiar with the essential mineral zinc. However, they may not know much about it beyond its name. They may correlate it to the scientific periodic table of the elements, or in helping with the common cold. But zinc is in fact required for activity in over 100 different enzymes (1).
Beyond that, it is also involved in DNA and protein synthesis (2), as well as supporting normal growth. For all of the above-listed reasons, as well as its involvement in numerous aspects of cell metabolism, deficiency in this mineral can be very problematic. It is therefore vital that you obtain enough into your daily diet.
Why Is Having Enough Important?
Since the body cannot store zinc (3), a daily, regular intake is vital for optimal, and even average, health. A deficiency can result in growth retardation, hypogonadism, immune dysfunction and cognitive impairment (4). Nearly 2 billion people in the world are deficient (5).
Zinc has also been shown to help with colds, which is how most people initially become aware of its physiologic importance (5). Taken within 24 hours of initial symptoms, it can help to reduce the duration of the common cold. Regarding dosage, around 75mg daily has been shown to work best.
About 25% of the world’s population does not eat enough zinc on a daily basis (6). Logically, it should then be obvious that increasing intake of zinc-rich foods is the best preventive measure to avoid a deficiency. Other proposed (though less individually feasible) methods include increasing amounts of zinc in the soil, as well as in crops.
If deficient, the most common clinical manifestations are malaria, pneumonia, and diarrhea. However, these are somewhat extreme cases. Mild deficiency manifests more subtly as lack of appetite, loss of smell or taste, and/or mild depression. Other symptoms shown can be weak immune system, hair loss and/or acne.
Zinc is a part at least 3,000 different proteins in your body. It can increase your production of white blood cells, as well as helping to increase cells that fight cancer (7). As stated, more than 200 different enzymes contain this mineral as well.
Zinc And Enzymatic Reactions
Since the 1980s, zinc has been much more well-studied and understood, especially in regards to its role in enzymatic reactions. As noted by researchers, it is required for essential catalytic functions in enzymes (more than 300) (8). In fact, some research has suggested that the human genome encodes around 3,000 proteins of this mineral (9).
Some research has also shown that zinc has a protective effect on oxidative stress enzymes in the liver (10). Further in regards to the liver, elevated amounts of hepatic vitamin A seem to be related to a zinc deficiency (11). This is both an example of how vitamins and minerals work together synergistically, as well as an example of why minerals and vitamins need to be kept within certain ranges. Too much of something can be just as detrimental as too little.
If you are male, you may want to consider that low levels of cellular zinc concentration have been linked to low levels of serum testosterone (12). This means that if you want to be in optimal health, it is vital that you get enough every day. Remember, it cannot be adequately stored by the body, so a deficiency can happen relatively quickly. Plummeting testosterone levels are not desired by any males that I’ve ever met!
Besides testosterone, zinc has been studied in regards to lowering infection rates (13). Researchers found that after supplementation, the incidence of infections was significantly lower. They also showed that plasma zinc was significantly higher. The correlation is very important, and is perhaps the single best example of direct benefits in both the human body and in the overall population. In the same study, researchers also showed that generation of tumor necrosis factor alpha and oxidative stress markers were significantly lower in those who supplemented with zinc. Have I beaten you over the head with how important this undervalued mineral is yet?
Zinc is also ubiquitous in sub cellular metabolism (14), and, as stated prior, is an essential component of the catalytic site of at least one enzyme in every enzyme classification (15). Interestingly, zinc supplementation has also been studied to possibly help with ADHD, which has risen in frequency as of late (16, 17). Whether or not this therapy works only in persons deficient in zinc remains to be seen.
Good Sources of Zinc
Oysters are by far the best source of zinc. Containing roughly 445% of your required daily value (18), in just 58 calories, oysters also contain high amounts of vitamin B12, copper and selenium – all vital to good health.
Lamb is the next best choice. About 50% of your daily required value of zinc can be found in just 3oz. of lamb (19). Since most lamb is grass-fed, it is a highly beneficial food to eat, since it’s also high in vitamin B12, protein, selenium, vitamin B3 and phosphorous.
Next on our list is spinach, which also happens to be high in vitamins A, C and K (20). Spinach also contains supportive nutrients called glycoglycerolipids, which are vital to photosynthesis and also have been shown to protect the lining of the digestive tract (21). Epoxyxanthophylls are also plentiful in spinach, and they’re being studied for possible anti-cancer effects (22).
Cashews come next on our list of zinc-rich foods. Cashews are rich in magnesium, copper and manganese as well (23). Though nuts, like cashews, are very high in omega-6, which is generally inflammatory, they are also a good way to fill in your diet with healthy fats.
Egg yolks are another secondary choice of zinc. Egg yolks are also rich in choline, and also have many other good nutritional components, such as selenium (24). I’m not quite sure where the recommendation of simply eating the egg white came from, but it is woefully misguided. This is doubly true for those that buy omega-3 enriched eggs, as the omega-3 content is in the yolk, not the white (25).
Many Americans choose to supplement with zinc in addition to obtaining the mineral from diet. Since zinc isn’t easily absorbed on its own, it tends to be bound to other substances, through a process called chelation. This helps to make the zinc more bioavailable, so humans can use it more effectively.
Zinc can be blocked by physic acid (26), so it is important to make a note of this, not only when supplementing, but when choosing foods to include in your diet. I recommend you check out my article on anti-nutrients, for more information about phytic acid.
The Bottom Line
Hopefully I have proven that this mineral is a generally overlooked element that is a vital part of a healthy lifestyle. The effects of a deficiency are both unpleasant and surprisingly widespread (27). Since many Paleo-friendly foods contain zinc, it is a good idea to incorporate a few of them into your daily diet. So remember to eat as many oysters as possible, and perhaps look into a good supplement, if you feel you need one.