Moderate dairy intake protects against COVID-19

17 Nov 2022 bởiStephen Padilla
Moderate dairy intake protects against COVID-19

Modest consumption of total dairy may lower the likelihood of contracting COVID-19 by 37 percent, while a higher intake of low-fat dairy products provides a protective benefit, reports a study.

However, greater consumption of high-fat dairy products, such as high-fat milk, total yogurt, cheese, and butter, appears to increase the risk of SARS-CoV-2 infection.

“Although our study has promising results, up to now, the number of researches in this field is not enough to provide reliable nutritional recommendations, and stronger clinical studies are needed to prove these hypotheses,” the researchers said.

A total of 8,801 adults aged 20‒70 years participated in this study. The research team obtained data on dietary intakes using a validated food frequency questionnaire. They then assessed the relationship between dairy consumption and COVID-19 through multivariable logistic regression analysis.

Moderate intake of total dairy (odds ratio [OR], 0.63, 95 percent confidence interval [CI], 0.46‒0.87; ptrend=0.97) was associated with a reduced possibility of COVID-19, and a higher intake of low-fat dairy products (OR, 0.51, 95 percent CI< 0.37‒0.69; ptrend<0.001) and low-fat milk (OR, 0.47, 95 percent CI, 0.35‒0.64; ptrend<0.001) could protect against COVID-19 after adjusting for confounders. [Eur J Clin Nutr 2022;76:1583-1589]

In contrast, increased intake of high-fat dairy products (OR, 1.40, 95 percent CI, 1.09‒1.92; ptrend=0.03), high-fat milk (OR, 1.54, 95 percent CI, 1.20‒1.97; ptrend<0.001), total yogurt (OR, 1.40, 95 percent CI, 1.04‒1.89; ptrend=0.01), cheese (OR, 1.80, 95 percent CI, 1.27‒2.56; ptrend=0.001), and butter (OR, 1.80, 95 percent CI, 1.04‒3.11; ptrend=0.02) correlated with a higher chance of COVID-19.

“There are some hypotheses about the etiology of relation between dairy consumption and COVID-19,” the researchers said. “Milk and dairy products are rich in protein, zinc, selenium, vitamin A, vitamin D as well as vitamin B12.” [J Am Coll Nutr 2011;30:415S-421SS; BMC Psychiatry 2020;20:1-8]

Dietary selenium consists of antioxidant enzymes glutathione peroxidase and thyroxine reductase, which are highly expressed in immune cells such as T lymphocytes and macrophages. Selenium has been reported to provide protection against RNA virus infections. [Adv Nutr 2015;6:73-82]

Zinc, on the other hand, is vital for many enzymes to function and for immune cell development. Sufficient zinc intake from food sources also keeps immune cells healthy and lessens vulnerability to infections like pneumonia. [Mol Med 2008;14:353-357; Annu Rev Nutr 2004;24:255-275; Annu Rev Nutr 2004;24:255-275]

For other micronutrients, vitamin A regulates the differentiation and function of immune cells such as monocytes and T cells, while vitamin D modifies the host’s immune pathway. [J Clin Med 2018;7:258; Curr Osteoporos Rep 2009;7:58-63]

“Evidence offer that vitamin D3 supplementation may reduce susceptibility to respiratory infection [46] or improve recovery from COVID-19, influenza, recurrent pneumonia, and tuberculosis,” the researchers said. [Int J Clin Pract 2021;75:e13748; BMJ 2017;356:i6583]

“In addition, proteins in dairy and peptides derived from them including, casein and whey protein, have antioxidant antiviral, anti-inflammatory properties in lung cells and regulate immune responses,” they noted. [Front Nutr 2021;8:394]