Foods That Boost Immune System


One of the most difficult aspects of foods that boost immune system and provide good immune health is that there is no particular food by itself that can be used to boost immune system.

Vitamins, minerals, antioxidants, phytochemicals, micronutrients and macronutrients that are found in food differ in quantities for each food. These work together and they depend on each other to achieve the optimal goal of keeping the immune system healthy and strong.

To find out what superfoods are and why a certain food may be included on the list check out our


One of the things that make a food a superfood is the amount of antioxidants it contains (measured in Oxygen Radical Absorbency Capacity - ORAC). High ORAC value is one of the several requirements for a food to qualify as a superfood. Below you will find the charts for the amount of ORAC in certain foods, some of which are foods that boost immune system and are on our list of superfoods.

ORAC Fruit Chart

ORAC fruit chart

* while pecan nuts, walnuts and ginger root are not fruits, we have added them to the fruit chart because of their high ORAC values, and as a comparison with fruit.

ORAC Spice Chart

ORAC spice chart

ORAC Vegetable Chart

ORAC vegetable chart

If we want to understand the importance of consuming a variety of foods that boost immune system we must first understand some of the basic nutrient interactions. The following list is a short list of how some nutrients interact and should give you an idea of some of the complex processes that occur in the body:

  • Glutathione recycles vitamins C and E and puts them back to work as antioxidants.

  • Cells do not produce Glutathione without the precursor amino acid components: glutamate, glycine and cysteine.

  • Low intracellular Glutathione levels cause the cell's death.

  • The conversion of beta-carotene to vitamin A depends on the availability of vitamin C, zinc and thyroid hormones while vitamin C, E and selenium enhance the function of beta-carotene.

  • Magnesium is necessary for conversion of vitamin B1 (thiamine) into its active form, and vitamin C helps improve thiamine absorption.

  • Vitamin B2 (riboflavin) is necessary for the activation of vitamin B6.

  • Vitamins B6, B2 and iron are necessary for the conversion of tryptophan (an essential amino acid) to vitamin B3 (niacin).

  • Tryptophan is a biochemical precursor for serotonin which in turn can be converted to melatonin.

  • Folic acid requires vitamin B12, niacin and vitamin C to be converted to its active form.

  • Vitamin C helps reduce folic acid excretion.

  • Vitamin C increases the absorption of iron and improves the stability of vitamin E.

  • Vitamin B6 deficiency reduces vitamin B12 absorption.

  • Vitamin D is necessary for the absorption and metabolism of calcium and phosphorus.

  • Vitamin B5 (pantothenic acid) is necessary for the synthesis of vitamin D.

  • Vitamin E is necessary for the action of vitamin A and regulates the levels of that vitamin.

  • Potassium decreases urinary loss of calcium, etc.

The intricacies and interdependency of vitamins, minerals, antioxidants, phytochemicals, micronutrients and macronutrients is much farther reaching than this short list, but hopefully this list is exhaustive enough to drive home how important it is to maintain a diverse diet.

Most foods that boost immune system are those that are good sources of one or two particular vitamins, minerals or nutrients, so eat a diversity of foods. For the immune system to function properly and be able to defend your body against pathogens, it is very important to supply the body with a sufficient amount of all vitamins, minerals, antioxidants, and amino acids. Immune health and proper immune response cannot be obtained without all these essentials.

Facts About Vitamins is where you can find useful information about all vitamins: their role in health, daily recommended amounts, toxicity and best food sources.

In addition to vitamins and minerals, there are three amino acids of particular importance to your immune health called Glutathione precursors - glutamate, glycine and cysteine - the so-called building blocks for your body's master antioxidant and immune booster Glutathione (GSH).

Foods that boost immune system work at elevating Glutathione by providing a variety of antioxidants that the body needs which in turn frees up Glutathione.

Note: glutamate and glycine are readily available in food for intracellular Glutathione production (all meats, poultry, fish, eggs, beans, dairy). Cysteine, however, is a limiting factor - its content in food is quite low, and for cysteine to be able to enter the cell it MUST be in proper undenatured bonded form (as two molecules bonded together). Pasteurization at high temperatures of milk, cheeses, yogurts and other dairy products, where cysteine content is the highest, destroys this bond making this cysteine practically useless for building intracellular Glutathione. No one food (even foods that boost immune system) contains all three amino acids in sufficient quantities to improve your immune health. That is why it is very important to eat a well balanced varied diet to ensure consumption of all three Glutathione precursors.

US Dietary Guidelines describe a healthy diet as one that:

  • Emphasizes a variety of fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products.

  • Includes lean meats, poultry, fish, beans, eggs, and nuts.

  • Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.

  • Stays within your daily calorie needs.

  • And most importantly - include proper rest and exercise (though not truly dietary, if you do not get these as well, you will not achieve the healthy you that you are striving for).

It is important to keep in mind that foods that boost immune system which we eat today are not what they used to be even 50 years ago. The well-known saying "An apple a day keeps the doctor away" is not as applicable as it once was.

Today you need to eat a dozen or more apples to get the same nutrient content as we did when this saying was originated. This is because the nutrient content of food has been reduced due to depleted soils, the use of pesticides and herbicides, processing and pasteurization, wholesale farming techniques that require collection of fruits and vegetables when they are not ripe. In many cases months pass before product reaches the shelves in the supermarket. Most vitamins, in fruits and vegetables, only have a shelf life of up to a few weeks after picking.

The best way to insure the quality of the produce you are eating is to shop for seasonal fruits and vegetables at the local farmers markets, at organic food stores, or grow them yourself. As for nutrients, it is well documented that processing/cooking destroys most of them. An example is the bonded cysteine molecule in cow's milk, which is one of the Glutathione precursors, - heat and mechanical stress break it down making this dietary cysteine source useless for building intracellular Glutathione as I have already mentioned above.

One more thought to keep in mind - not all foods that boost immune system work the same for all people due to possible allergy reactions, levels of oxidative stress, health of digestive system, or underlying medical conditions.


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