Zinc deficiency is widespread in NZ. These are the foods to eat to avoid itby Jennifer Bowden
New Zealanders are falling short of our daily zinc requirements leading to deficiency, but a diverse diet can boost levels of the mineral.
It plays a role in immune function, wound healing, protein and DNA synthesis and cell division. That makes it crucial for normal growth and development during pregnancy, childhood and adolescence. Zinc is also needed for our senses of taste and smell, appetite, and sperm generation.
Zinc is an all-rounder when it comes to metabolic duties. This means that zinc deficiency can affect health in ways such as growth retardation, loss of appetite and immune-system impairment. A severe deficiency can lead to hair loss, diarrhoea, delayed sexual maturation, impotence, hypogonadism in males (diminished functional activity of the gonads), eye and skin lesions, weight loss, delayed wound healing, taste abnormalities and mental lethargy.
Our bodies can’t store zinc for future use, so a good daily supply is crucial. In New Zealand, the recommended daily dietary intake is 14mg for men and 8mg for women. However, New Zealand’s most recent National Nutrition Survey, conducted in 2008, found the median daily intake was 12.9mg and 9mg for men and women respectively.
In other words, many New Zealand males are falling short of their daily zinc requirements, along with adolescents and institutionalised elderly.
Zinc deficiency is common in very young children and is linked to an increased risk of infection and poor growth. Recent New Zealand research found 60% of surveyed infants had plasma zinc concentrations below the recommended level.
Infants and toddlers may be at greater risk of zinc deficiency because the types of foods typically offered at the first stage of weaning aren’t particularly high in absorbable forms of the mineral. Breast milk is not capable of making up that shortfall, as it doesn’t contain enough zinc to meet the needs of infants six months and older.
Nonetheless, zinc is widely available in the food supply – though it is more bioavailable from animal products than plant foods. Red meat, oysters, lamb’s liver and cheese have the highest concentrations of zinc, but other protein-rich foods such as chicken, fish and eggs are also good sources, as are cereal grains, legumes and nuts.
We are absorbing little bits of zinc from many of the wholefoods we eat. For most New Zealanders, beef, bread, pasta and other grains contribute nearly a third of our requirements. Dairy, vegetables and poultry also make significant contributions.
University of Otago researchers found that intake of red meat and zinc-fortified infant formula were linked to higher zinc status in infants. Food fussiness was also linked to their zinc status, they noted in the March issue of the journal Nutrients.
Given that zinc is involved in our sense of taste, it’s possible that too little of the mineral could turn children into fussy eaters, which in turn restricts their diet and zinc intake.
In the 1970s, British researchers found that giving young zinc-deficient children supplements led to improvements in their sense of taste and food intake.
The best solution to our zinc needs is to eat a varied diet containing lean meats, fish, eggs, fruits, vegetables, grains, dairy, nuts and seeds.
This article was first published in the June 9, 2018 issue of the New Zealand Listener.
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