High Fat Diet Affects Immune Cells in Arteries
Node Smith, ND
A new study from La Jolla Institute for Allergy and Immunology looked at the immunological effects of a diet high in fat and cholesterol.1 The study intended to give further insight into the relationship between arterial cholesterol and the immune system in promoting the inflammatory process which ultimately results in plaque buildup in the arteries. The study shows that a diet high in fat and cholesterol (a Western Diet) decreases the number of protective immune cells, switching them into cells which promote inflammation and atherosclerotic plaque buildup. The research also showed that HDL -”good cholesterol” – does the opposite.
Atherosclerosis is actually an immune disease
Commenting on current understanding of cardiovascular disease, Dalia Gaddis, Ph.D., a postdoctoral researcher, places the immune system center stage, “People think atherosclerosis is just about cholesterol, diet, and exercise, but it’s actually an immune disease. The blockage of arteries is very much due to the immune system reacting to excess cholesterol and lipids in the walls of blood vessels.”
Regulatory T cells – Tregs – singled out for this study
Since different types of immune cells play different roles in atherosclerosis, regulatory T cells – Tregs – were singled out for this study. Tregs are known to prevent the development of atherosclerosis. Previous research has shown that when animals are fed a diet similar to a Western diet – high in fat and cholesterol – Tregs decline. This current research tracks this process to find out what is happening to them.
Tregs switch to follicular helper T cells – Tfh
It was found that a high fat and cholesterol diet signaled Tregs to switch to follicular helper T cells – Tfh. This cell type is important in the body’s handling of viral and bacterial infections – little had been known of their impact in atherosclerosis. It seems that the Tfh cells were actually promoters of atherosclerosis, and that when this cell line is blocked, a significant reduction in the development of arterial plaque is observed in animals fed a Western diet.
Research also looked at HDL
The research looked at HDL as well. It noted that HDL prevented the loss of Treg cells. This was tested by administering apolipoprotein AI to the animals. With such treatment the animals fed the Western diet did not show a switch to Tfh cells.
More research in the consideration of immune function and the development of cardiovascular disease is warranted
The researchers did comment that this does not necessarily hold true to human populations, however it does further support the consideration of immune function in the development of cardiovascular disease.
- Gaddis DE, Padgett LE, Wu R et al. Apolipoprotein AI prevents regulatory to follicular helper T cell switching during atherosclerosis Nat Commun. 2018; 9(1).
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Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.