Zinc is a clever little mineral which is crucial to human health. It is important for immune function, wound healing, digestion, healthy hormones, libido, brain function, sperm development, thyroid function, fertility, pregnancy, growth and development in children, healthy hair, skin and nails, and a whole lot more!
How much zinc do we need?
The Recommended Daily Intake (RDI) for zinc is 8mg/day for women, 14mg/day for men and 11mg/day during pregnancy, as set by the National Health and Medical Research Council (NHMRC) and the Australian Government Department of Health.
Zinc is one of the most important nutrients required during pregnancy. Deficiency is correlated with infertility, foetal growth malformation, maternal stretch marks and postnatal depression.
What are the consequences of low zinc intake?
Any or all of the symptoms below can be influenced by low zinc levels*:
- Poor immunity e.g. recurrent colds
- Poor memory
- Difficulty concentration
- Skin blemishes and acne
- White spots on nails
- Urinary tract infections (UTI’s)
- Poor wound healing
- Fussy eating in children
- Infertility in both men and women
- Low sperm count/poor sperm quality
- Polycystic ovarian syndrome (PCOS)
- Behavioural problems in children
- Digestive issues including bloating and reflux
*Please note: the above signs and symptoms can also be indicative of other nutrient deficiencies and/or health conditions. A nutrient deficiency should not be assumed and supplementation should not be commenced without seeking professional advice from your healthcare practitioner.
Which foods contain zinc?
Oysters are by far the highest source of zinc, followed by red meat, eggs, organ meats (e.g. liver) and other seafood. Plant based sources of zinc include:
- Whole grains
- Pumpkin seeds/pepitas
- Raw cacao
- Wheat germ
- Flax seeds
The requirement of zinc in vegans and vegetarians are usually higher than meat eaters because often a plant based diet contains large amounts of grains and legumes (this is not a bad thing, hello fibre!). However, given that plants, grains and legumes are the main source of phytates and oxalates, which prevent zinc absorption, this should be considered when trying to optimise zinc status.
Does anything reduce the absorption of zinc?
Like iron, there are many substances which can decrease the absorption of zinc, including:
- Phytic acid found in whole grains (brown rice, quinoa, buckwheat, oats etc) and legumes (chickpeas, lentils, beans etc) bind to zinc in the gastrointestinal tract and prevent its absorption. Correct preparation of legumes and grains should be emphasised in order to optimise absorption of zinc and other minerals. Rinsing and soaking these foods prior to cooking helps to de-activate phytic acid
- Oxalates found in foods such as tea, spinach, rhubarb and kale bind to zinc in the gastrointestinal tract and prevent its absorption. Lightly cooking leafy greens reduces the oxalate content significantly
- Tannins found in tea and coffee (even some herbal teas, and especially green tea)
- Other divalent minerals: iron, calcium, magnesium, copper (take such supplements 2 hours away from zinc supplements*)
- Low stomach acid (i.e. people who take antacids or proton pump inhibitors for heartburn/reflux/gastroesophageal reflux/GORD/GERD^)
- Digestive/malabsorption issues such as IBS, undiagnosed/unmanaged coeliac disease and inflammatory bowel conditions i.e. Crohn’s disease
*Speak to your healthcare practitioner before commencing any supplement use. ^Do not cease taking prescription medication unless advised by your healthcare practitioner.
To sum up…
So we know that zinc is SUPER important for all things immunity, fertility, skin, hormones, mood, gut health, memory… and the list goes on! And we know that if we are vegetarian or vegan we need to correctly prepare our lentils and grains to reduce phytates and oxalates to optimise zinc (and iron) absorption. And if we take any calcium, iron or magnesium supplements then these should generally be consumed 2 hours away from zinc supplements (but we should always talk to our healthcare professional about taking any supplements because we want to make sure we are taking the best thing for us, because we are all completely unique and amazing individuals!). Concentrating on getting enough zinc into our diets should be a top priority as the seasons change, winter draws closer, noses start to sniffle and the dreaded flu starts to show itself again. To read more about boosting your immune system and food as medicine for the coming colder months, click here!
Image source: The Veda House