Why eating foods high in zinc is good for the body?

Zinc supplementation pills
Zinc supplementation.

Zinc is an essential trace mineral that plays a vital role in almost every aspect of our health. It’s the second most abundant trace mineral in our bodies (1). The first one is iron. Zinc is important to growth, immunity, wound healing, acne, tasting, smelling, reproduction and many more. We can prevent zinc deficiency through diet or supplementation.

Diseases and zinc

Zinc is required for the activity in more than 100 enzymes (2). Most enzymes are composed of a protein and a cofactor. A cofactor can be an essential mineral, like zinc, or a vitamin. If the essential mineral or the vitamin isn’t available, the enzyme underperforms. As you understand, zinc is a key component of many aspects of our health.

Zinc and immune system

Zinc deficiency caused either by inadequate zinc consumption, either inefficient absorption can depress immune function in many ways (2,3).

In zinc deficiency:

  • can impair natural killer cell activity, like white blood cells.
  • the number of T cells may reduce.
  • can lower thymic hormone levels, which are important for immune system development and function (4).
  • increased susceptibility to pneumonia and other infections in children and the elderly (2).

In zinc ambulant:

  • can promote the destruction of foreign microorganisms.
  • can help against free radicals damage.
  • promotes proper white blood cell function.
  • inhibit the growth of some viruses, like common cold viruses (5,6).

Role of vitamin C and zinc for colds and flu

As previously mentioned, zinc can inhibit the growth of common cold viruses. The main type of zinc intake is by zinc lozenges. Many studies have conducted to determine the role of zinc in cold viruses. Although the results are conflicting, scientists believe that overall zinc appears to be beneficial under certain circumstances (2).

However, more research is needed, before zinc can be recommended as a treatment for the common cold. Differents parameters can cause very different results. Further research is needed, to determine:

  • the best dose,
  • form of zinc, and
  • how long it should be taken

In general, zinc lozenges can provide relief of sore throat due to the common cold and even reduce the duration of symptoms of the common cold (6).

Zinc, along with vitamin C are critical nutrients for the proper immune system functions. Both zinc and vitamin C can impair antiviral activity. Vitamin C has consistently decreased the duration of cold episodes and the severity of symptoms. The common cold studies indicate that infected from common cold people, they may need extra amounts of vitamin C to deal with the flu (9). Additionally, vitamin C supplementation may be beneficial in people exposed to brief periods of severe physical exercise or cold environments (7).

zinc supplemens for colds and flu
Role of vitamin C and zinc for colds and flu

We know that individually vitamin C and zinc play an important role in immune defense. What about combining the intake of both? A 2012 study did that exactly. Researchers studied the results of two double-blind, randomized, placebo-controlled trials. In these studies, researchers combined 1000 mg vitamin C with 10 mg zinc in patients with the common cold. The results? Scientists observed that the combination of vitamin C with zinc was significantly more efficient than a placebo at reducing rhinorrhoea over 5 days of treatment. In addition to that, symptom relief was quicker (10).

Taking a supplement does not replace a well-balanced diet

Don’t forget though. Taking an artificial supplement of any vitamin or other nutrient does not replace a good well-balanced diet. It’s always better to provide your immune system daily with steady amounts of vitamin C and zinc at the same time. A whole food plant-based diet is perfect for that.

Best zinc lozenge for colds

There are many studies examining the effect of zinc treatment on cold symptoms. The results are conflicting, although overall zinc appears to be beneficial under certain circumstances (2). The form of zinc is the first parameter that scientists investigate. The second parameter is the extra substances in zinc lozenges. You should prefer sorbitol, mannitol, and citric acid free zinc lozenges. They are sweeteners. Why is that?

It appears that in order for zinc to be effective, it must be ionized in saliva. The presence of sorbitol, mannitol or citric acid can suppress the ionization of zinc in saliva (11). Also, you better prefer zinc acetate or gluconate lozenges.

Zinc and fertility

Zinc is a very important trace mineral for proper male sexual functions. It is mainly found in the prostate, testes, and semen.

It is a key element for the male reproduction process. Zinc is responsible for (12):

  • hormone metabolism
  • sperm motility
  • sperm production
  • sperm count
  • sperm morphology
  • protection against free radical damage, as it has antioxidative properties. Sperm is very vulnerable to free radical damage.

Consider, that in every ejaculation 2.5 mg of zinc is lost.

Many studies have suggested that zinc supplementation can help men on sperm motility and sperm counts. Especially if someone has low testosterone levels. Testosterone can be increased as well (13).

Zinc and erectile dysfunction

As we previously discussed, zinc is a key factor for a healthy male reproduction process. Zinc is concentrated in semen. Frequent ejaculations can be the reason for zinc deficiency. If zinc stores in the body aren’t restored, the body tries to take care of itself. The aftermath is to rise a defensive mechanism, in which there isn’t a sexual drive. That way the body can restore the zinc in the body in proper amounts.

The best way to overcome erectile dysfunction, caused by zinc deficiency, is by a whole food plant-based diet. The zinc richest foods may be oysters, meat, and especially the liver, but it is very important to consume daily vegetables, fruits, whole grains, legumes, nuts, and seeds.

Other essential nutrients, except zinc, for sexual drive and function, are omega-3 fatty acids, vitamin A, and vitamin E.

Zinc in pregnancy and lactation

Mild-to-moderate zinc deficiency may be relatively common worldwide, but zinc deficiency during pregnancy maybe even higher. It is estimated that over 80% of pregnant women worldwide have inadequate zinc intake (14,15). Pregnant women consume on average 9.6 mg zinc per day, while it is recommended to consume at least 11mg zinc per day during pregnancy and 12 mg daily during lactation (2).

These low daily zinc intake can increase the risk of having zinc deficiency, as fetal has high zinc requirements. The same stands for lactation, during maternal zinc stores, can be dangerously decreased.

Maternal zinc deficiency may:

  • compromise infant development
  • lead to poor birth outcomes.
  • affect a big amount of hormones, important during pregnancy
  • affect mather’s and fetus’s immune system or even be the cause of preterm birth (14,16)
  • cause low birth weight or prematurity
Zinc in pregnancy and lactation
Zinc needs in pregnancy and lactation.

Considering these, it is thought that the daily recommended zinc intake of 11mg is important for improving pregnancy outcomes for mothers and infants (14).

Zinc for hair loss

There is some research if zinc deficiency can affect hair loss. The results are promising. For instance, in research for the role of zinc in hair loss, 9 of the 15 patients, that took a zinc supplement, had positive therapeutic effects (17). Scientists suggest that zinc supplementation may help people with hair loss problems if they have a zinc deficiency. Zinc supplementation could be an additional therapy for hair loss, especially when the traditional therapeutic methods have no success.

Other important nutrients for healthy hair are vitamin A, essential fatty acids, like omega-3 fatty acid and iron. A whole food plant-based diet can help you consume, the natural way, the recommended daily intake for these important nutrients.

Zinc and diabetes

Zinc is very important to diabetics, as they can excrete high amounts of zinc in the urine. It is suggested that diabetics should take 30mg zinc daily, in an attempt to avoid zinc deficiency.

Some diabetics can experience difficulty in the proper absorption of some micronutrients. Such abnormal metabolism of several micronutrients in diabetic individuals isn’t uncommon. Zinc is one of the essential micronutrients of which metabolism can alter under diabetes and even zinc deficiency can play an important role in the development of diabetes (18).

Also, zinc is part of insulin synthesis, secretion, and utilization. Zinc deficiency could be of huge importance in diabetes. As mentioned before, zinc is a key factor in the immune system and has antiviral effects. It can even inhibit the growth of some viruses, like common cold viruses (5,6).

Zinc and acne, skin, wound healing

Zinc is also an important micronutrient for the normal function of skin. Proper zinc intake can accelerate wound healing, contrary to zinc deficiency which is associated with impaired wound healing (20). Also, doctors frequently treat skin ulcers with zinc supplements (2).

Zinc has antiageing properties.

Zinc may help in acne problems, although more research is needed. Nonetheless, zinc supplements have helped patients with inflammatory acne, as zinc can act as anti-inflammatory (21).

Furthermore, zinc has photoprotective and elastic regenerative properties. Researches suggest that it could be used for antiageing purposes (19).

Zinc and cancer

As we discussed already, zinc is important for the proper functions of our immune system, and it protects our body from free radicals damage. Also, it functions as an antioxidant and anti-inflammatory agent (22).

Oxidative stress and chronic inflammation can be partly the reason for the development of many cancers (22)

Researches have found that 65% of patients with head or neck cancer were zinc deficient. They suggest that further studies should be conducted, in order to be found the importance of zinc on cancer. They found that zinc supplementation can be helpful against cancer. Zinc can suppress cancer by decreasing angiogenesis and inflammation. At the same time, zinc can increase apoptosis in cancer cells (22).

In addition to the above, researchers have found that vitamin and mineral supplements can be used for reduced risk of prostate cancer (23).

Why not taking these vitamins and minerals directly from food? A whole food plant-based diet is the best way to supply your immune system with every micronutrient it needs to protect you against cancer. A vegan diet, except for healthy, can be cheaper, than buying artificial commercial supplements. Also, consider, that micronutrients can act more efficiently when they are in balance. Food is the only way to keep everything in balance.

Zinc and depression

Zinc is an important modulator to our nervous and immune systems. Its deficiency is related to human depression.

It has been proven that zinc enhances the antidepressant effect in laboratory animals, so its potential therapeutic value in human depression must be further studied (24).

Zinc is a promising supplementation to treating depression.

Furthermore, a placebo-controlled double-blind study of zinc supplementation in antidepressant therapy showed that patients with major depression significantly reduced their depression scores after 12 weeks, compared with the placebo group of patients. Patients took daily zinc supplementation, along with the standard antidepressant therapy. The benefits of zinc supplementation in antidepressant therapy were promising (25).

So, what’s the zinc recommended daily intake? The amount of zinc you need daily depends on your age.

RDI for children

The RDI for children depends on the age. 0-3 years should consume about 3mg of zinc daily (2). Under normal circumstances, this wouldn’t be difficult to reach. Most baby formulas are zinc fortified. A study analyzed the concentrations of zinc in infant formulas and human milk during lactation and found that the values of zinc concentration were similarly, about 3-4 mg/L in each case (26). Infant zinc deficiency is rather uncommon in developed countries.

As you can see, baby formulas contain adequate amounts of zinc (28):

Food description (100gr)Zinc (mg)
Oatmeal cereal, baby food, dry, instant10,99
Multigrain, whole-grain cereal, baby food, dry, instant6,67
Mixed cereal, baby food, dry, instant6,66

Teenagers of both saxes have higher demands on zinc. They should consume at least 8mg of zinc daily. Boys should consume at least 11mg of zinc daily and girls 9mg. In the case of pregnancy, girls should consume 12mg of zinc daily (2).

AgeRDI
0–6 months2 mg
7–12 months3 mg
1–3 years3 mg
4–8 years5 mg
9–13 years8 mg
14–18 years9-11mg

RDI for women

As you can see in the table, women should consume about 8-13mg of zinc daily. You better concern about your daily zinc intake during pregnancy and lactation, as the demands on zinc are slightly bigger. Always consult your doctor.

AgeFemalePregnancyLactation
14–18 years9 mg12 mg13 mg
19+ years8 mg11 mg12 mg

RDI for men

Men have bigger demands on zinc, partly because of the amount of zinc lost in semen (about 2.5 per ejaculation) and high demands on zinc in the male reproduction system. They should consume at least 11mg of zinc daily.

AgeMale
14–18 years11 mg
19+ years11 mg

What’s the maximum zinc daily intake?

The maximum zinc daily intake is shown in the below table per age group. Long-term intakes above the upper level of daily intake can increase the risk of adverse health effects (2). These upper levels do not apply to patients who receive zinc for medical treatment. The patient’s physicians should monitor for adverse health effects.

Tolerable Upper Intake Levels for Zinc:

AgeMaleFemalePregnantLactating
0–6 months4 mg4 mg
7–12 months5 mg5 mg
1–3 years7 mg7 mg
4–8 years12 mg12 mg
9–13 years23 mg23 mg
14–18 years34 mg34 mg34 mg34 mg
19+ years40 mg40 mg40 mg40 mg

What are the signs of a zinc deficiency?

Zinc deficiency is often associated with other health conditions. Always consult your physician if you experience one or more of these symptoms.

Zinc deficiency symptoms (2):

  • unusual growth
  • impaired immune function
  • loss of appetite
  • hair loss
  • diarrhea
  • delayed sexual maturation
  • eye lesions
  • skin wounds
  • weight loss
  • delayed healing of wounds
  • taste abnormalities
  • mental lethargy

Consider that the major losses of zinc from the body are through the intestine, the urine, and in sweat (28). So, high consumption of alcohol, extreme weather conditions or intense exercise can lead to excess loss of zinc. We should concern about extra zinc intake in these conditions, as the body has no zinc stores in the conventional sense.

Which foods are high in zinc?

According to the World Health Organisation, lean red meat, whole-grain cereals, pulses, and legumes provide the highest concentrations of zinc. Concentrations in such foods are generally in the range of 25–50mg/kg (380–760mmol/kg) raw weight (27).

Processed cereals with low extraction rates, polished rice, and chicken, pork or meat with high-fat content have moderate zinc content, typically between 10 and 25mg/kg (150–380 mmol/kg).

Fish, roots and tubers, green leafy vegetables, and fruits are only modest sources of zinc, having concentrations <10mg/kg (<150mmol/kg).

Saturated fats and oils, sugar, and alcohol have very low zinc contents.

As you can see in the following table, if you are a healthy person and follow a well-balanced diet is rather difficult to have a zinc deficiency, as many common foods are good sources of zinc. If you have high zinc needs you can add a little amount of animal protein in your food. A research of the University of Gothenburg of Sweden has suggested that even relatively small amounts of animal protein can significantly improve the value of a legume-based meal as a source of zinc (29).

For vegans, zinc supplementation is the easiest way, for extra zinc intake. But there are many common foods rich in zinc, for vegetarians and vegans, like, whole-grains, legumes, beans, seeds, and nuts, as you can see in detail in the following paragraph.

Food description (100gr)Zinc (mg)
Cereal, bran flakes51,7
Oysters, raw39,3
Wheat germ, with sugar and honey13,88
Milk, malted, dry mix, not reconstituted13,64
Cereal, toasted oat13,39
Oatmeal cereal, baby food, dry, instant12,68
Multigrain, whole-grain cereal, baby food, dry10,67
Mixed cereal, baby food, dry, instant10,66
Sesame seeds10,23
Beef, stew meat, cooked, lean only10,18
Deer, stewed8,59
Beef jerky8,11
Pork jerky8,11
Yeast7,94
Pumpkin seeds, unsalted7,64
Lamb hocks, cooked7,63
Pumpkin seeds, salted7,55
Wheat bran, unprocessed7,27
Beef brisket, cooked, lean only eaten6,83
Chocolate beverage powder, dry mix6,82
Cocoa powder, not reconstituted6,81
Pine nuts6,45
Octopus, dried6,37
Cereal, granola6,3
Ground beef, cooked6,2
Mixed seeds5,88
Squid, dried5,79
Beefsteak, fried, lean only eaten5,77
Cashews, unroasted5,6
Sunflower seeds, plain, unsalted5,29
Goat, baked5,23
Shrimp, dried4,96
Tahini4,62
Pecans, unroasted4,53
Cheese, Cheddar, reduced fat4,44
Flax seeds4,34
Chia seeds4,34
Brazil nuts4,06
Peanut bar3,94
Cheese, Swiss, reduced fat3,9
Seaweed, dried3,9
Cheese, Gouda or Edam3,8
Popcorn, microwave, plain, light3,8
Trail mix with nuts3,75
Cheese, Cheddar3,64
Oats, raw3,64
Peanut butter, lower sugar3,51
Mixed vegetable juice3,47
Vegetable mixture, dried3,36
Almonds, NFS3,31
Almond butter3,29
Peanuts, unroasted3,27
Almonds, unsalted3,21
Soy nuts3,14
Oat bran, uncooked3,11
Walnuts3,09
Peanut butter2,51
Soybean meal2,46
Hazelnuts2,45
Egg, yolk only, raw2,3
Baked beans, vegetarian2,28
Crackers, rice2,2
Pesto sauce2,09
Tomatoes, red, dried1,99
Bread, whole wheat, toasted1,94
Hummus, plain1,74
Yogurt, Greek, low-fat milk, plain0,6

Data from the US Department of Agriculture (28).

Vegan foods rich in zinc

So, what about a vegan diet? Can a healthy vegan be deficient in zinc? Although oysters and red meat have a good reputation in their rich content on zinc, you shouldn’t concern if you prefer a whole food plant-based diet.

As you can see in the previous table there are many vegan foods rich in zinc. For example:

Wheat germ, whole-grain cereals, sesame seeds have more than 10mg/100gr.

Yeast, pumpkin seeds, chocolate powder, cocoa powder, pine nuts, granola cereals, cashews, sunflower seeds are good zinc sources (5-10mg/100gr).

Tahini, pecans, flax seeds, chia seeds, Brazilian nuts, peanuts, seaweed, popcorn, oats, walnuts, hazelnuts, legumes, pesto sauce, tomatoes, whole wheat bread, hummus and many more, have decent amounts of zinc.

Try to eat many of these foods daily. As you can see, on a vegan diet isn’t difficult to achieve your daily zinc recommended intakes.

Are vegans deficient in zinc?

A vegan diet has been blamed for inhibiting the absorption of zinc. The reason is the high presence of phytates (inositol hexaphosphate) in a vegan diet. Phytates are mainly present in whole-grain cereals and legumes, as well as seeds and nuts. Other vegetables can contain phytates but in insignificant amounts. Phytates form an insoluble mass by chelating with zinc, inhibiting absorption zinc absorption. This procedure has been demonstrated in humans (28).

So what’s the solution?

Germinate seeds, grains and legumes.

  • Firstly, you can add to your meals white beans and lupin-based products. Zinc absorption from lupin protein is comparable with that from animal protein-based diets despite a higher phytate content in the former (30). Lupin beans can be ground into a flour and used as an additive to wheat flour, enhancing the flavor to foods. They can also be used as a key ingredient in animal-free milk and meat replacement. They also are sold in jars in a brine.
  • Secondly, it may be a good idea to avoid excess calcium intake. High dietary calcium can enhance the act of phytates, challenging zinc absorption in experimental studies (27).  
  • Thirdly, remember that the availability of zinc from the diet can be improved by reducing the phytate content. Soak beans, grains, and seeds for 12–24 hours. Let them sprout. Germinating seeds, grains, and legumes can reduce the phytate content.
  • Fourthly, an additional reduction of phytate content can be achieved by fermentation (27, 31). Fermented foods are rich in probiotic bacteria. As a result, by consuming fermented foods you are adding beneficial bacteria to your intestinal flora, increasing the good gut microbiome and enhancing the health of your digestive system. You can experiment with the fermentation of porridge or dough for bread making.
  • Don’t worry about high dietary fiber content in your diet. Fibers do not interfere with zinc absorption (31).

Don’t worry about the zinc absorption in your vegan diet. The total amount of zinc is more important. Studies have shown that the total amount of zinc in a meal may have a better effect on overall absorbed zinc than the presence of phytate. For example, white and wholemeal bread compared to their zinc absorption. White bread has lower zinc content but better bioavailability of the whole-grained bread, due to the lack of phytates. In the end, though, whole-grained bread resulted in more zinc being absorbed (32).

Sources:

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  33. Foto by, pexels.com/photo/color-drugs-medicine-pills-415804/