We may take it for granted that our diet can influence the way our immune systems work. But how and why does what we eat impact the immune response? In this Honest Nutrition feature, we investigate.
The immune system is a
The immune system offers two lines of defense: innate immunity and adaptive immunity.
Innate immunity is the first line of defense and consists of physical barriers, such as the skin and mucous membranes and chemical and cellular defenses. The innate immune system is
If the innate immune system is ineffective against a potential threat, the adaptive immune system takes over.
The adaptive immune system consists of specialized blood cells and proteins that target the specific cause of infection. The adaptive immune system has a “
A person’s immune system needs to function well for them to remain healthy. Certain illnesses, medications, and lifestyle choices, such as
Research shows that a person’s diet can impact immune health as well.
For example, nutrition can affect the microbiome, gut barrier function, inflammatory processes, and white blood cell function,
Dietary patterns and individual foods have associations with increased disease risk, greater risk of allergy, and impaired immune response.
Western-type diets tend to contain high levels of saturated fat, ultra-processed foods, added sugar and salt, and overall calories. This diet is often low in foods associated with better health, such as vegetables, fruits, and fatty fish, and has strong links to an increased risk of chronic disease.
Research suggests that Western-type diets induce inflammation and alter immune system function, promoting disease development.
In contrast, diets rich in whole foods, such as vegetables, fruits, nuts, legumes, and seafood, and low in ultra-processed foods can reduce disease risk and promote healthy immune function.
Additionally, a deficiency or insufficiency of nutrients essential to immune function, including vitamin D, zinc, and vitamin C, can also affect immune response.
Although it is clear that dietary choices impact overall health, including immune function, the interaction between diet and immune health is highly complex. Scientists are still learning how the foods a person consumes may help or harm immune function.
Western-type diets tend to be high in refined carbohydrates, added sugars, saturated fat, and calories. This pattern of eating affects immune function in several ways.
Most of the foods in Western diets are ultra-processed and contain high levels of added sugar, which can promote inflammatory responses of the immune system.
For example, foods and beverages that significantly impact blood sugar levels, such as soda, candy, sugary cereals, and sugary baked goods, increase levels of
Higher blood sugar levels have links to an
Also, diets high in added sugar and refined carbs may
A healthy microbiome is essential to immune function because gut bacteria play a
Experts have also linked Western-type diets to an altered immune response due to high levels of saturated fat and added salt.
Diets high in added salt have links to
Western-type diets have links to an increased risk of developing several chronic diseases, including certain cancers, heart disease, and type 2 diabetes.
Researchers attribute this to the chronic low-grade inflammation and altered immune response that Western-type diets, sedentary lifestyles, and toxin exposure cause.
However, research investigating the relationship between diet and immune function is ongoing, and scientists do not entirely understand this complex relationship.
While a diet high in ultra-processed foods, added sugar, and excessive calories may lead to immune dysfunction, dietary patterns rich in whole, nutrient-dense foods are beneficial for immune function.
The Mediterranean diet is rich in vegetables, legumes, nuts, fruits, whole grains, olive oil, and other healthy foods. Research has shown that it can reduce disease risk, lower markers of
Diets high in fiber, such as the Mediterranean diet, promote the production of
SCFAs act locally and systemically to modulate the immune response. They maintain the health of and improve the immune defensive function of the intestinal epithelium. This is an important part of the immune system that serves as a barrier against microorganisms. It also reduces the production of inflammatory proteins from immune cells.
Diets high in fruits, vegetables, olive oil, nuts, seeds, and fatty fish contain high levels of nutrients, such as vitamin A, vitamin C, zinc, vitamin D, B6, B12, copper, folate, iron, and selenium. The immune system needs these nutrients to
Experts know that vegetarian-based diets reduce markers of chronic inflammation, such as CRP, fibrinogen, and IL-6. This might be partly due to the array of nutrients and nonnutritive components found in fruits and vegetables strengthening the immune system response.
Foods rich in healthy fats, fiber, vitamins, protein, minerals, and beneficial plant compounds help reduce systemic inflammation, promote healthy gut bacteria balance, reduce oxidative stress and cellular damage, and improve blood sugar and insulin sensitivity. All of these activities are essential for
To support immune function, a person should concentrate on following a balanced dietary pattern rich in whole, nutrient-dense foods, especially plant foods, such as vegetables, fruits, legumes, nuts, and seeds. People should avoid or limit ultra-processed foods high in refined grains and added sugar.
It is essential to follow a healthy diet to ensure good immune function.
Studies show that while certain dietary patterns may lead to impaired immune function, other dietary patterns promote optimal immune function.
A dietary pattern low in ultra-processed foods and rich in whole, nutrient-dense foods, such as vegetables, fruits, fish, and legumes, protects against chronic disease risk and supports a healthy immune response.
Following a healthy dietary pattern and leading a lifestyle that includes stress reduction techniques, restful sleep, daily physical activity, and other healthy habits is the best way to support the immune system and reduce disease risk.