What are the health benefits of zinc in your body?
Zinc is an essential nutrient that is a cofactor for hundreds of enzyme reactions in the human body.
Zinc is critical to a wide range of functions, including immunity, reproduction, skin health and vision.
Zinc deficiency symptoms
A large portion of the population is at risk of being zinc deficient.
Dietary zinc deficiency is associated with impaired growth and development in children, pregnancy complications, and immune dysfunction with increased susceptibility to infections.
Zinc deficiency is more common in the developing world where animal products are harder to obtain in the food system, affecting an estimated 2 billion people.
Consumption of diets high in phytate and low animal-based foods can drive exacerbate zinc deficiency.
Zinc deficiency symptoms include:
- low testosterone,
- poor night vision,
- acne zinc,
- amnesia,
- brittle nails,
- loss of taste and appetite,
- decreased leptin levels,
- decreased immune function,
- diarrhea,
- low stomach acid,
- depression,
- emotional disorders,
- Hypogonadism (i.e. diminished production of sex hormones in the teste or ovaries),
- hypercholesterolemia, and
- impaired cognitive function.
Can zinc deficiencies cause lines in your fingernails?
Ridges in your fingernails can be an indication that your body is low in protein, calcium, zinc, or vitamin A.
Can zinc boost your libido?
Zinc is vital to the development and function of the male sex organs.
Males with zinc deficiency have been shown to have less developed testes and a lower sperm count.
Zinc supplements are often used as a treatment for erectile dysfunction as zinc helps produce sex hormones, such as testosterone and prolactin.
How much zinc is required daily?
Our satiety analysis indicates a moderately strong satiety response when people consume foods and meals that contain more zinc.
The average zinc intake for Optimisers was 20 mg/2000 calories with an 85th percentile of 35 mg/2000 calories. This is more than the Estimated Average Requirement of 12 mg/day for men and the Daily Recommended Intake of 14 mg/day.
Zinc toxicity level and upper limit
There is no evidence of adverse effects of high amounts of zinc in foods, and hence, there are no real symptoms of toxicity or side effects. You will quickly excrete any excess zinc in the faeces. However, an Upper Limit of 40 mg has been set for zinc from supplements.
Zinc stretch target
Based on our satiety analysis, we have set a stretch target of 32 mg/day for men and 25 mg/day for women.
| nutrient | average | EAR | RDI | UL | stretch (men) | stretch (women) |
| zinc (mg) | 20 | 6.5 | 8 | 40 | 32 | 25 |
Availability of zinc in the diet
Zinc availability in the food system has increased since the 1930s with the widespread fortification of breakfast cereals. As shown in the chart below, there was a significant jump in zinc fortification in the mid-1970s (data from USDA Economic Research Service).
The current level of zinc in the diet still does not meet the Daily Recommended Intake or Estimated Average Requirement and is nowhere near the stretch target. So most people will need to pay attention to zinc to ensure they get enough in their diet to achieve more ideal intake levels.
What factors interfere with zinc absorption?
Absorption of zinc is impacted by excess sugar, insufficient stomach acid, gut inflammation and allergies.
Excess calcium intake impairs zinc absorption as do excess phytates (found in grains and legumes).
Iron and zinc compete for absorption pathways, so excess iron supplementation or fortified foods can negatively impact the absorption of zinc.
If your ratio of iron:zinc is greater than 2:1, then your absorption of zinc will be reduced.
Absorption from animal sources of zinc is much higher than from plant sources, so strict vegans should allow an additional 50% more zinc in their diet.
Too much zinc can interfere with your absorption of copper and vice versa. Hence, it’s ideal to maintain your zinc:copper ratio between 10:1 And 15:1.
Nutrient Optimiser ensures that you do not prioritise more zinc in your diet if you don’t already have enough copper.
Storage
Zinc is stable, so your food will go bad before the zinc content changes significantly.
Synergistic nutrients
Zinc works synergistically with vitamins A, B6, D, E, cysteine, glutathione, magnesium and manganese. Hence, it is crucial to get your zinc from nutrient-dense whole food sources that typically come packaged with these other nutrients.
Processing losses
Zinc in meat is not significantly depleted by cooking. However, you will lose some zinc via the liquid when cooking vegetables.
Soaking and sprouting beans, seeds and grains may improve zinc bioavailability.
Zinc-rich foods
Foods that contain more zinc tend to be shellfish, liver or non-starchy green vegetables as listed below. Keep in mind here that animal-based sources of zinc will also be more bioavailable.
Animal
- ground beef
- Parmesan cheese
- milk
- whole egg
- brie
- cottage cheese
Seafood
- oyster
- crab
- crayfish
- squid
- shrimp
- anchovy
Plants
- parsley
- asparagus
- zucchini
- broccoli
- lettuce
- cucumber
- kale
- cauliflower
- sauerkraut
Nutrient profile
The nutrient fingerprint shows the availability of nutrients in the foods that contain the most zinc. We can get adequate levels of zinc from nutrient-dense foods. Foods that are high in zinc are generally very nutrient-dense, have a low energy density and significant levels of protein.
Nutritious foods and meals to boost your zinc
If you are experiencing any of the symptoms of low zinc or are concerned that your current zinc intake is low (e.g. due to a heavily grain-based processed diet with less protein), then you may be interested in our lists of zinc-rich foods and meals.
What you will get:
- Our Nutritional Optimisation Kickstart Guide,
- A list of the most popular 50 foods that contain more zinc,
- A longer list of 100 popular foods that contain zinc, and
- A more extended list of 150 common foods that contain zinc to allow you to expand your nutrient-dense repertoire further.