As little as 4 milligrams of supplementary zinc every day could prevent DNA damage, a new study suggests.
Zinc is vital for human development during pregnancy, childhood, and adolescence; it is involved in many aspects of cellular metabolism and cell division.
The mineral also plays a role in DNA synthesis, protein synthesis, and helps our body to heal its wounds. Zinc can limit inflammation and oxidative stress, which means that it may also protect against cardiovascular disease and some cancers.
With time, our DNA deteriorates, but the human body also has the ability to regenerate it until late adulthood. However, insufficient zinc compromises the body's ability to repair everyday DNA "wear and tear."
The daily amount of zinc, as recommended by the National Institutes of Health (NIH), is 8 milligrams for women and 11 milligrams for men, although guidelines differ according to age.
New research - published in the American Journal of Clinical Nutrition - suggests that an additional intake as small as 4 milligrams per day can have a positive impact on cellular health, as well as help the human body to fight off infections.
Assessing the effect of 'modest' dietary zinc increase on the human body
Researchers from the UCSF Benioff Children's Hospital Oakland Research Institute (CHORI) in California set out to determine the impact of a small increase in dietary zinc on metabolic functions and measures of zinc status in the body.
Led by CHORI Senior Scientist Janet King, Ph.D., the team tested the effect of an increase equivalent to that which biofortified crops provide in the diet of populations that are nutrient-deficient.
The authors explain that while food fortification slightly raises the zinc content of cereals such as wheat and rice, few studies have shown a positive effect on the functional indicators of zinc levels in the human body.
Researchers designed a randomized, 6-week controlled study where 18 men consumed a low-zinc, rice-based diet.
The diet consisted of 6 milligrams per day for 2 weeks and continued with 10 milligrams daily for the remaining 4 weeks.
Before and after the diet, the researchers measured zinc homeostasis indicators and other metabolic indicators, including DNA damage, DNA inflammation, and oxidative stress.
Modest increase in zinc reduces DNA damage
The study revealed significant changes in the zinc homeostasis indicators.
Scientists found an increase in the levels of total absorbed zinc, while plasma zinc concentrations and the exchangeable zinc pool size remained the same.
Leukocyte DNA strand breaks were also reduced with increased dietary zinc, which suggests that a modest increase in zinc reduces the everyday "wear and tear" of the DNA.
This is the first time that a small increase in dietary zinc has been shown to reduce oxidative stress and DNA damage.
"We were pleasantly surprised to see that just a small increase in dietary zinc can have such a significant impact on how metabolism is carried out throughout the body. These results present a new strategy for measuring the impact of zinc on health and reinforce the evidence that food-based interventions can improve micronutrient deficiencies worldwide."
Janet King, Ph.D.
King suggests that biofortification could be an effective and sustainable solution to malnutrition and zinc deficiency.