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Immune Boosting Foods

Updated: Sep 3, 2020

On Wednesday evening, I participated in a professional development phone call for Food for Life Instructors with Dr. Neal Barnard. For those who are not familiar with Dr. Barnard, he is the founder of the Physicians Committee for Responsible Medicine (PCRM) and an Adjunct Associate Professor of Medicine at the George Washington University School of Medicine in Washington, D.C. The author of 16 books including Dr. Barnard's Program for Reversing Diabetes, Dr Barnard is an NIH-funded nutrition researcher. He shared with us what we can still do to help ourselves to be armed against this virus in the best possible way. The following is what I learned.

In this present crisis, there is still plenty of time to get your nutritional house in order.

How do you do that? You tackle the risk factors. If you have high blood pressure, diabetes, excess weight or lung disease, you can begin to mitigate those factors right now by adopting a whole-foods, plant-based diet (WFPB). Let's take a look at each risk factor.

1. High Blood Pressure: Dr. Barnard shared with us that 40% of those with severe covid-19 infection had high blood pressure before they were infected. High blood pressure damages your arteries and your heart. The virus attaches to ACE 2 enzymes and blood pressure medications may increase this enzyme - the welcome mat for the virus. A WFPB lowers blood pressure by making the blood less fatty increasing its ability to flow and by providing potassium which lowers blood pressure. Plants are also naturally very low in sodium.

2. Diabetes: This known risk factor for covid-19 complications can also be aided by a WFPB diet. How? When you eat a diet that is naturally low in fat you are getting the fat out of your cells and thereby allowing the insulin to work as the key that allows blood glucose to enter your cells. Typically, blood sugar drops in a matter of days when you move to a WFPB diet.

3. Excess Weight: Our white blood cells recognize, engulf, and destroy viruses. Excess body weight reduces these killer cell's ability to do their job in two ways. First, there is a mechanical issue as excess fat restricts the lungs. Second, in an Australian study of older men with high fat versus low fat diets, the participants on the high fat diet had impaired production of white blood cells. While the mechanism as to why this is so is unclear, it does appear that with a higher fat diet we can't make white blood killer cells as well.

4. Lung Disease: A respiratory virus that settles into a comprised lung is not a good scenario. WFPB diets improve lung health and particularly the avoidance of dairy helps asthma. Some studies show reducing the fat in the diet can help too.

Dr. Barnard also reviewed some foods and compounds that have been popularly reported to be helpful for viruses and while they may have shown effectiveness against other viruses understand that these have not been tested against covid-19.

Garlic: In a large 12-week study with 146 people, 1/2 of the participants took a garlic supplement and the other half took a placebo during cold season. The placebo group had 65 cases of colds versus only 24 in the garlic group. The placebo group took a combined 366 sick days versus 111 for the garlic group. Thus, garlic seems to be effective.

Resveratrol: Found in grapes, blueberries, strawberries and some in peanuts, resveratrol helps inhibit the multiplication of viruses but more research is needed.

Ginger: While ginger is clearly anti-inflammatory, its action against viruses is less clear. More study is needed here as well.

Beta Carotene: This compound gives fruits and vegetables their orange color (think carrots), but there have been mixed findings on their immune boosting power.

Vitamin C: Seems to have enough published data to show that it is helpful in fighting off viruses. Remember there is no vitamin C in meat, dairy, or fish!

Vitamin D: This is a controversial "vitamin" (it's actually a hormone) in terms of supplementation. It is naturally produced when unprotected skin is exposed to the sun, but since most of us don't get enough sun, supplementation is recommend though the amount is debated. In a meta analysis of studies including 11,000 people, those who supplemented with vitamin D had a 12% respiratory disease risk decrease. Dr. Barnard's recommendation is 2000iu per day.

Coldeez: These are those little sugary lozenges which are reported to shorten the duration of a cold. That appears to be true. Zinc is the active ingredient, but when you don't have a cold virus, zinc can impair the immune system so best not to take it unless fighting a cold.

I would like to have asked Dr. Barnard about other foods such as turmeric and mushrooms (see Magical Mushroom Vegetable Soup) which Dr. Michael Gregor has researched and reported to have immune boosting properties, but time did not permit. Dr. Barnard did answer a few questions about elderberry syrup, echinacea, and nasal rinses and reported that he does not believe there is any proven efficacy in those.


The virus is here and your best defense is a good offense. Practice good hygiene, socially distance yourself, don't smoke, and tackle your vulnerabilities by adopting a healthy diet that is low-fat, and loaded with fruits and vegetables to boost your immune system. Is a WFPB diet a panacea? We don't have that evidence, but can it hurt? No. Can it benefit? Absolutely!

If you'd like to try a whole-foods, plant-based diet but don't know how to get started, try my Easy 3-step Plan.


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