Foods That 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.

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).

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. Check out the only available dietary source of undenatured bonded cysteine.

No one food contains all three amino acids in sufficient quantities to boost the immune system. That is why it is very important to eat a well balanced varied diet to ensure consumption of all three Glutathione precursors.

• 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 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.

Several vitamins have a special effect on the immunity. Their sufficient consumption, according to the studies, delivers a better immune response, which lowers the incidence of infection and may help prevent diseases. These are vitamins C, A (in beta-carotene form), B6, E and D.

Foods which contain glutamate, glycine and cysteine - Glutahione building blocks - also contribute to improving immune health (even though cysteine content in foods is very low and it rarely reaches the cells in the desired undenatured form).

There is a number of foods that truly stand out because of the high nutrient and/or antioxidant content in them, thus making them superfoods. Incorporating them into your diet daily promotes immune health.

I have put together a list of foods that we strive to include into our menu regularly. To make navigation through these foods easier for you I listed them in alphabetical order.


ALFALFA - Alfalfa contains 8 essential enzymes needed to effectively digest food; it is rich in vitamins (A, E, and K) and minerals (calcium, iron, manganese, potassium, magnesium). Alfalfa is also a good plant source of protein (0.5 oz. per 3.5 oz. of weight according to USDA). Alfalfa has been shown to aid in lowering cholesterol and regulating bowels, as well as in getting rid of excess fluids in the body. It helps fight off infections - the chlorophyll in alfalfa develops an effective barrier against bacterial invasion.

ALMONDS - only one ounce of almonds (about 20-24 shelled whole nuts) contains 35% of daily recommendation amount of vitamin E. Almonds are also a good source of omega-3 fatty acids - heart-healthy unsaturated fats that lower your bad cholesterol.

BEANS - Beans or legumes are a good choice when trying to incorporate additional servings of vegetables into your diet. Beans are rich in potassium, B vitamins, and fiber which promotes health of the digestive system. Beans are a source of glutamate and glycine - two of the three precursors for Glutathione production. Cooked beans are low in calories, contain very little fat and are also considered a meat replacement food. As a tip, try substituting beans for meat twice a week. Also, beans contain health-promoting substances called saponins in their cells. Clinical trials suggest that saponins may help lower cholesterol, lower blood glucose responses, and have been shown to have an inverse relationship with the incidence of kidney stones. Isn't it remarkable that beans are even shaped like human kidneys?

BERRIES - Berries are loaded with vitamin C, potassium and fiber. They have some of the highest antioxidant levels of any fresh fruits. Berries which are deep red and blue in color (blueberries, strawberries, blackberries) contain very beneficial phytochemicals. Studies have shown that strawberries are involved in inhibiting inflammation enzymes. Plus, berries are simply delicious! Scoop some on top of your cereal in the morning or mix them into your yogurt.

BROCCOLI - Broccoli is rich in vitamin C and dietary fiber. Small amounts of selenium, a co-factor of Glutathione production, present in broccoli. It is also an excellent source of several compounds and chemicals that have been clinically proven in laboratory and animal studies to have anti-cancer, anti-bacterial and anti-viral properties, and to boost DNA repair in cells. These chemicals are diindolylmethane, glucoraphanin, sulphraphane and indole-3-carbinol (or I3C). The health benefits of broccoli are greatly reduced if this vegetable is boiled. Steaming and stir frying do not appear to destroy these compounds. Other cruciferous vegetables - cauliflower and Brussels sprouts - contain these beneficial chemicals in them as well.

CHERRIES (tart) - Tart (sour) cherries are the only natural source of melatonin in the amounts that can effect your health: melatonin helps increase your master antioxidant Glutathione without which cells die. These dark colored cherries are also rich in anthocyanins. It is very difficult to find fresh sour cherries even during season, so they are available as dried or frozen cherries and tart cherry juice concentrate which preserves perfectly all the goodness of this fruit.

CHOCOLATE - Cocoa powder used in the production of chocolate has very high antioxidant capacity measured in ORAC, even higher than blueberries, strawberries and garlic. Antioxidants found in cocoa enhance vascular function and decrease platelet stickiness contributing to cardiovascular health. Just remember to choose dark semi-sweet chocolate with cocoa content not less than 70% (baker's chocolate is a good choice), and please do not make the whole bar disappear in one sitting!

FISH - Fish is a good source of easily digested protein, low in saturated fat, rich in omega-3 fatty acids. Omega-3 enriched diets are associated with the reduction in incidence of heart attacks, and higher fish intakes (salmon, trout, herring, cod, tuna, and sardines) were associated in several studies with a lower incidence of coronary artery disease and cardiovascular mortality. Overall it has been shown that a minimum of one fish meal a week on a regular basis translates into a 52% reduction in sudden cardiac death. Fish is also one of the very few sources of vitamin D, and a good source of glutamate and glycine - Glutathione building blocks.

GARLIC - In addition to wide culinary uses garlic is also well known for its medicinal properties backed by extensive research. Garlic has antibacterial, antifungal, antiviral and anti-inflammatory properties and that puts it right into the super food category. Garlic boosts immune system, helps reduce blood clotting and blood pressure, helps reduce cholesterol. Garlic contains small amounts of cysteine, one of the three precursors for Glutathione production. It is a good idea to add fresh garlic to your everyday diet, especially during winter flu season. We usually chop some on top of our salads every day at dinner time. A good tip: for enzymes in garlic to be activated you must cut or chop it before adding it to the dishes you cook. Chewing would do it if you prefer to eat it raw without cutting it. Just don't eat it on an empty stomach as it may cause irritation.

GINGER - Just like garlic ginger is both a culinary spice and a medicinal super food. It acts as an antioxidant and has antibacterial, anti-inflammatory and anti-clotting properties. It has been shown to improve liver function, digestion and help lower cholesterol. Ginger has also been used to treat motion sickness and nausea. It is important to remember not to eat ginger on an empty stomach as it may cause irritation too like garlic.

KALE - You often see kale used as a background decoration for serving sandwiches or shrimp at buffet parties, and it gets thrown out afterwards. It also adorns flower beds in summer. However, kale is very rich in antioxidant nutrients and should be added to your menu. Kale is very high in beta-carotene (vitamin A forming carotene), lutein and zeaxanthin (other two carotenoids considered beneficial for maintaining good eye health), vitamin C, vitamin K and calcium. Tip: kale has very hard stems, so before cooking it or chopping it into your salad, remove the stems completely even out of the leaf part itself. Kale freezes well too, and freezing actually adds a bit of sweetness to the taste. Because of high vitamin K content in this plant, people taking anti-coagulant drugs should avoid eating kale.

KEFIR - Kefir is a fermented probiotic milk drink made by communities of lactic acid bacteria and yeasts called "kefir grains". These kefir grains look like cauliflower florets, and can be placed in cow's, goat's or sheep's milk to make kefir. The taste of kefir is mildly to strongly sour depending on the length of fermentation, usually 12-24 hours at room temperature. In the process of fermentation of lactose kefir grains produce dozens of varieties of highly beneficial probiotic bacteria which assist in maintaining the health of the digestive system, and improving absorbtion of vitamins and nutrients from food. Kefir is reported to be well tolerated by lactose intolerant people, because kefir grains consume all lactose from milk. The best milk to make kefir is raw unpasteurized milk which contains all the nutrients, vitamins and enzymes including those necessary for proper lactose digestion that are destroyed by pasteurization (lactose intolerance is actually intolerance of pasteurized milk lacking enzymes - something that FDA and milk industry do not want you to know). Kefir is sold commercially at health food stores and some supermarkets, however, it is of course pasteurized, and probiotics, usually only 4 or 5 varieties, are then added back to it along with sugar, flavorings and food dye to make it more appealing to consumers. The best way to experience all the health benefits of kefir containing a multitude of live probiotic cultures is to purchase kefir grains from a local dairy farm or online and make your own kefir. It can be also used to make delicious sourdough whole grain bread, pizza crust, or cream cheese. Find a raw dairy farm near you (in USA).


ONIONS - Phenol and flavonoid compounds in raw onions are known for their antioxidant properties that strengthen immune health. Mild tasting varieties have lesser antioxidant activity than those that "bite". Onions are also one of the few sources of cysteine, an all important building block for Glutathione.

PARSLEY - Fresh parsley is a great source of vitamin C, it is also rich in vitamin K, iron, zinc, folate, magnesium and dietary fiber. However, as with kale, because of very high vitamin K content, parsley should be avoided by those taking anti-coagulants and by pregnant women as parsley oils could lead to stimulation of uterus and preterm labor. One or two sprigs on a salad should not be a problem though (if you are pregnant ask your doctor if eating parsley is ok for you in case you are at risk for miscarriage).

QUINOA - Quinoa (pronounced /'keenwa/) is a grain native of South America. It can be cooked pretty much like rice but has much higher nutritional value than any other grain. Quinoa is rich in vitamins B1, B2, B6 and E, folate, iron, magnesium, zinc, selenium, and phosphorus. The most remarkable thing about quinoa is that it contains all amino acids (including glutamate, glycine and cysteine for Glutathione production) in such proportions as to make quinoa a complete protein - very unusual among plant foods. The protein content of quinoa is very high (14%). It is gluten-free, so it is very easy to digest. Quinoa is also a good source of dietary fiber. All these nutritional qualities make quinoa a must, in my opinion, for a well balanced diet aimed at improving immune health.

Quinoa in its natural state has a coating of bitter-tasting saponins that need to be removed before cooking. Soaking quinoa in water for 2 hours before cooking and rinsing it well under running water in a fine strainer will do that. Most packaged quinoa available at supermarkets has saponins already removed (check the packaging).

Cooking quinoa: bring two cups of water to a boil, add one cup of quinoa, cover and simmer on low for about 15-20 minutes until water is gone, fluff up with a fork and serve. It can be boiled in vegetable or chicken broth to add flavor. Quinoa can be eaten as is or mixed with steamed greens (spinach, kale, broccoli), fried mushrooms, added to cold salads; for nutritious breakfast - mixed with a bit of honey, almonds, dried tart cherries, raisins or fresh berries. Bon appetit!

WALNUTS - Walnuts are rich in quite a few nutrients that are very important to your immune health. They contain vitamins B1, B2, B6, E, folate, and selenium necessary for the production of Glutahtione. All amino acids are present in walnuts including Glutahtione precursors glutamate, glycine and cysteine. Walnuts are also rich in two most important co-factors of vitamin D production - magnesium and zinc. Other nutrients present in walnuts in significant quantities are iron, phosphorus, copper, manganese, potassium, lutein and zeaxanthin, and omega-3 fatty acids. Walnuts are also rich in fiber and protein. All these facts make walnuts a real nutrition powerhouse. Make sure you add them to your menu - in salads, cereals, yogurt, trail mix, baking!

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