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# Vitamin D deficiency is why you get flu and other infections
- URL: https://www.foodconsumer.org/vitamin_d_deficiency_is_why_you_get_flu_0703100554/
- Published: 2010-03-07T17:53:00.000Z
- Updated: 2026-09-22T15:42:32.000Z
- Description: A University of Copenhagen study in Nature Immunology reports that T cells need vitamin D to activate against bacteria and viruses. Carsten Geisler's team traces the signalling chain from the T cell receptor through the vitamin D receptor gene to PLC-gamma1.
- Author: Food Consumer
- Tags: Vitamins, Nutrition, Vitamin D, #vivvo-import

A new study led by researchers at the University of Copenhagen has confirmed that vitamin D plays an important role in activating immune defenses against infectious diseases like flu.

Vitamin D deficiency has already been linked to a wide spectrum of diseases including heart disease, cancer, diabetes, depression, autoimmune disease and many others.

The study published in the latest edition of Nature Immunology discovers that activation of T-cells to fight infections needs definite help from vitamin D.

Carsten Geisler and colleagues, study authors, explained the role vitamin D plays in the immune responses as follows.

First when the naive T cell recognizes foreign invaders like bacteria or viruses with T cell receptor (TCR), it sends activating signals (1) to the vitamin D receptor gene. The VDR gene then starts producing DVR protein, which binds vitamin D in the T cell (3) and becomes activated. Then the vitamin D bound and activated DVR gets into the cell nucleus and activates the gene for PLC-gamma1 (5), which in turn produces PLC-gamma1 protein (6) and "the T cells can get started".

In the case of flu fighting, Dr. John Cannell and his colleagues have reported that vitamin D helps produce antibacterial peptides that help protect against flu. That is why in winter people are prone to becoming vitamin D deficiency and getting infected with flu viruses.

Dr. Cannell, a vitamin D expert and director of Vitamin D Council, says in his newsletter sent last year that two physicians, one in Wisconsin and the other in Georgia reported to him that few of their patients/residents who maintained a high level of serum vitamin d acquired swine flu last year while many of other patients and medical workers who did not take vitamin D to maintain high vitamin D levels got swine flu and other flu viruses.

By David Liu /Credit: Professor of Immunology, Carsten Geisler