In this article we are going to dive deeper into how diet and nutrition play a role in immune
function. Most diet related studies on immune related outcomes focus on specific
macronutrients, micronutrients, phytonutrients, herbs and probiotics. There are some general
principles that are helpful to build a strong immune system and metabolic reserve. These basic
Macronutrient insufficiencies and or frank insufficiencies contributes to immune suppression.
Both macronutrients and micronutrients play a vital role in immune function. Protein intake and
digestion is a concern in the elderly. Adequate amounts of protein are important for maintaining
building blocks for immune cell development and function. Elevated refined carbohydrates is
often considered to e harmful to the immune system. In a landmark study immune cell activity
was cut nearly in half for more than 5 hours after consumption of 100 grams of various forms of
sugar. Simple carbohydrate consumption are known to increase CRP with which is a marker of
increased inflammatory cytokines. Dietary fiber labeled as carbohydrates on the other hand are
beneficial to the immune system in multiple ways. Dietary fats are potent modulators of
immune function and act as mediators in certain pathways. All classes of fats with the
exception of trans fats are required for proper cellular and immune function. Typically, Omega 6
fatty acids are considered inflammatory and Omega 3 fatty acids are anti-inflammatory. Both
groups contain inflammatory and anti-inflammatory fatty acids. There are many different types
of fat and while fats have received a bad reputation in the media, the truth is, fats are a vital
part of a healthy diet.
The role of vitamins, minerals and other micronutrients for proper cellular function can not be overstated. Let us now look at the role of specific micronutrients and the role each plays in immune function.
Vitamin A is best known for being good for the eyes. Vitamin A is vital too many specific immune functions including maintaining epithelial and mucosal barriers. It also supports components of immune cell function such as lymphocyte differentiation, natural killer cell activity, antibody production and response.
Vitamin C is widely known for immune enhancement. Vitamin C is highly concerted in immune cells and low levels are directly related to lower immune function. Low levels are known to cause immune-system suppression while high levels are known to improve immune cell activities. Immune cells are susceptible to free radicals (oxidative stress). Vitamin C is a strong immune cell anti-oxidant and protects immune cells from damage.
Vitamin D3 research has greatly increased over the past few decades and its importance as a therapeutic agent is now widely excepted. With respect to the immune system, vitamin D acts to regulate a variety of immune processes including regulating T cell activation, natural hiller T cell activity and regulating both the innate and adaptive immune response. Deficiencies and insufficiencies of D levels are linked with increased levels of infection and immune dysfunction.
According to research data, neatly all un-supplemented Americans have a vitamin D level below optimal levels. For optimal immune health the target level for vitamin D3 is 40-70. Other data suggest slightly higher level of 50-80.
Zinc is a vital trace mineral involved in over 300 different enzymatic reactions in humans. Zinc deficiency suppress thymic function, T lymphocyte development, T-cell and B cell function and macrophage activity. There is no body store for zinc therefore constant intake through diet and or supplementation is required to maintain adequate levels.
I mentioned the importance of the mitochondria with respect to immune function in the first part of this article. In addition to the nutrients covered in this section I would like to look briefly at some nutrients specific to mitochondrial support. Vitamin E improves T cell proliferation and decreases oxidative stress. Selenium is a mineral that works synergistically with vitamin E. Selenium has been shown to improve a range of immune cell functions and activities. Other nutrient antioxidants such as lipoic acid N-acetyl cysteine (NAC), carnitine, and CoQ10 work as glutathione inducers or work by protecting the mitochondria from excessive oxidation and thereby improving immune function.
I would like to make a some finishing remarks and make a few points perfectly clear. Hopefully you can see that certain nutrients play an important roll in immune function. As most of my clients know, I recommend you get these nutrients from your diet when possible. There are some nutrients that need to be supplemented. I caution anyone to supplement without the recommendations of a trained professional. You can run the risk of over supplementing and disrupt the balance of nutrients causing unintentional health consequences. Use this information as motivation to improve your diet moving closer to a nutrient dense diet and not as an excuse to buy more supplements.
Next time we will look at how physical activity and how the bodies stress response affect immune health and function.
Health and happiness,