Can a bad diet affect your immune system?

by | Diet and Weightloss

A bad diet is another form of malnutrition, where the over-consumption of saturated fats has a detrimental effect on the immune system.

Sadly for many around the world, not having enough to eat each day leads to a suppressed immune system. The inability to mount an effective immune response increases the risks of contracting disease and reduces the ability to recover.

The suppressed immune response is the result of not getting enough energy and a deficiency of specific minerals and vitamins, both of which act to impair immune function. It is then paradoxical that people who are obese, a health condition of excess nutrient availability, also have impaired immune function.

One classic example is the reduced immune response to vaccination commonly found in obese people.

To uncover why obesity can also suppress the immune response, researchers at the Australian Research Council Centre of Excellence in Advanced Molecular Imaging at the University of New South Wales investigated this in an animal model.

They measured something unusual in the activation of T cells in rats fed a high fat diet.

T cells are a class of white blood cells that are a central part of the adaptive immune response. When the immune system confronts a bacteria or virus, it is the T cells that are able to hunt down and destroy infected cells.

In rats fed a high fat diet, after just a few days, the function of the T cells was reduced. This occurred well before the animals gained any additional weight due to the calorie-rich diet.

In looking further, T cells rapidly change the fats found in their cell membranes. The increase in saturated fat in the diet increases the amount of these fats in the cell membrane. The T cells then became sluggish and were not able to respond in their normal rapid ways to defend the body.


Consuming a junk food diet, rich in saturated fat, is likely to impair the action of the immune system by making T cells slow and sluggish. So obesity and a junk food diet is potentially another form of malnutrition, impairing the functions of the immune system.

This experimental research highlights how rapidly this effect appears to occur. This means that a healthy diet could have your T cells bouncing back to their fast acting ways in a matter of days.