Plant-Based Nutrition and the Human Immune System

Written by Dr. Sant Chaiyodsilp on Tue, 01 August 2023

Key Highlights

  • The Immune System - Before delving into what diet is good for your body and its immunity, it is important to understand the basic functioning of your immune system. This article throws light on the same so that you're able to understand the relevance of a plant-based diet towards your health.
  • Immunity Boosters - Dr. Sant lists down a few essential ingredients like turmeric, garlic, ginger, etc that are great in building a strong immunity and should be consumed in healthy quantities every day.
  • Case Studies - The article provides readers with a few case studies to prove the benefits of plant-based nutrition and the health threats of consuming meat.
  • Rainbow Diet - It is believed that a colorful diet is a healthy diet. Dr. Sant explains the benefits of consuming a variety of foods, in different colors and tastes to enhance your immunity.
  • Healthy Lifestyle - This article explains the importance of combining plant-based nutrition with other habits like exercising, getting plenty of sleep, and meditating for good mental health to be able to improve your immunity and lead a healthy life.

Living in a pandemic-stricken era means having to take extra measures to boost your immunity, and plant-based nutrition happens to be one of the best ways to achieve this. After conducting thorough research on this topic, medical experts have carefully concluded that a plant-based lifestyle can successfully boost your immunity and keep you from catching infectious diseases.

Recent research reveals that plant-based food such as whole grains, soy, legumes, fruits, nuts, and vegetables can reduce severe Covid by up to 73%. Moreover, they're also known to reduce the risk of cardiovascular and other chronic diseases related to the brain.

At the recently held Asian Plant-Based Nutrition Healthcare Conference, several doctors and medical experts gathered to discuss the benefits of taking up a plant-based lifestyle for improved health. Dr. Sant Chaiyodslip, MD, and Chief Wellness Coach at Mega Wellness We Care emphasized its benefits in strengthening your body's immunity.

To understand the impact of plant-based food on the internal functioning of your body and learn how to embrace healthy eating habits, read further:

Understanding the immune system

The Covid-19 Pandemic saw everybody go the extra mile in taking preventative measures to boost their immunity - be it resorting to homemade remedies like drinking herbal teas and decoctions or popping health supplements - without realizing that immunity should be paid attention to, at all times, regardless of being hit by a pandemic.

According to Dr. Chaiyodslip, it is essential to understand the functioning of the body's immune system and the processes that are involved in making or breaking it, before actually delving into the diet that one should follow to boost immunity. Elaborating on his point further, Dr. Sant explained, "The immune system is divided into two parts - the innate immunity that deals with any foreign organisms that enter your body, and adaptive immunity which creates antibodies and cells to deal with known pathogens."

"Now, there are antioxidants and free radicals that come in close contact with the immune system. These free radicals help in destroying viruses, bacteria, or toxins but the bad side of these free radicals is that they can damage tissue and cause cell aging," he continued.

Dr. Sant pointed out that while understanding your immune system, you must know about the reactive oxygen species (ROS) - radicals that are capable of reacting with oxygen. They are a result of the metabolism that takes place in the mitochondria of cells and are known to send signals to the immune system to work more or less, depending on the situation.

Talking about antioxidants, he said, "They are agents of detoxification or destruction of the reactive oxygen species, making them effective in fighting inflammation and boosting the body's immunity."

Explaining further, Dr. Sant mentioned there are two types of antioxidants - endogenous are those that are produced by our own body and exogenous are the ones that are derived externally, either from dietary sources or health supplements. The ones we gain from eating plants are called phytochemicals, and it is advised that our body receives antioxidants through whole foods and plants as opposed to taking supplements in the form of pills.

Immunity Boosters

Now that you're familiar with the fundamentals of how your immunity functions, we can now move on to Dr. Chaiyodslip's recommendations for your daily diet.

Here are a few ingredients known to boost your immunity

1. Turmeric

Now, it is not turmeric per se, but the curcumin in it that makes the difference. This active ingredient present in turmeric is a strong antioxidant and a great anti-inflammatory agent. It also has great antiviral and bacterial properties. However, it is difficult for the body to absorb curcumin. This problem can be fixed with the consumption of black pepper which contains piperine, which ensures its absorption.

It is also a very good immunomodulating agent, which means "it stimulates or suppresses the immune activities like antigen recognition process, phagocytosis, apoptosis, white blood cell production, white blood cell proliferation, antigen-antibody reaction and the release of cytokines."

Cytokines are pro-inflammatory signal molecules released by local cells to modulate the immune response. Any cell in the immune system can produce various types of cytokines. Also, curcumin protects the lung tissue from lethal pneumonia and Acute Respiratory Distress Syndrome (ARDS), caused by the suppression of many cytokines.

To highlight his point on turmeric, Dr. Sant put forth a case study that effectively proved the benefits of consuming turmeric:

In a recent medical study, 140 Covid patients were divided into three groups; those suffering from mild, moderate, and severe Covid. They were then divided into treatment and control groups where the treatment group received curcumin plus piperine twice daily through the consumption of turmeric and pepper combined with medical treatment, while the other group was just provided with a placebo. It was revealed that the treatment group showed significantly reduced symptoms of Covid in a shorter period. They were also discharged sooner from the hospital than other patients. Overall, this group showed a lower mortality rate than the patients who didn't make it in the treatment group too, but everyone who didn't make it was battling severe Covid.

2. Pepper

As mentioned earlier, pepper contains piperine which is beneficial in absorbing curcumin and is a great immunomodulating substance. Pepper is also said to increase phagocytic activity, a biological activity where the host protects itself from infectious environmental particles and cleanses the body of unwanted host cells to protect the tissues. Pepper inhibits inflammatory activity and the production of excess cytokines.

3. Mushroom:

Widely recommended to consume for cancer prevention and treatment, mushrooms have long been used in Asia. The beta-glucan from the mushroom is highly beneficial in curbing tumor growth in the body. It also defends the body against fungal, bacterial, and parasitic infections.

To confirm the immunomodulating property of mushrooms, a study enrolled participants for the prevention of upper respiratory tract infection. They were then divided into two groups. The first group was asked to consume oyster mushrooms and the other group received a placebo. It was found that the mushroom-eating group had significantly cut down their risk of upper respiratory tract infection.

4. Garlic

It enhances immune cell activities, including apoptosis and detoxification activities. It also reduces the chances of catching a common cold infection by 63%, and further decreases the duration of cold symptoms by 70%. There are more than 1,000 scientific publications about garlic and its health benefits. Garlic is an excellent immunomodulator and laboratory evidence suggests that garlic possesses certain healing properties which are required by your body.

5. Ginger

"We have a lot of laboratory evidence supporting ginger in immuno-modulation, but not enough evidence at the randomized controlled trial study in humans to conclude, or to draw any advice using ginger for particular health issues yet. However, you must know that ginger is known to down-regulate the expression of a gene controlling cells called antigen-presenting cells or APC," says Dr. Sant.

A Colorful Palette = Improved immunity

The above ingredients are just a few recommended for improved immunity. Dr. Sant firmly believes that "It is important to consume a large variety of foods each day.

There are at least four ways to ensure that we do this:

  • The first way is to consume as much whole food as possible; consume plant-based food in its most natural form.
  • The second way is to make your food palette as colorful as possible. As they say, turn your food palette into a rainbow because different colors denote different phytochemicals.
  • The third way is to experiment with your food based on its taste. Different phytochemicals produce different tastes. Consuming spices [and herbs regularly is a good way to expand the variety of food.
  • The fourth way is to look at seasonal foods and make them a part of your meal. Different foods come out in different seasons and in each season, the food processes different phytochemicals. In short, make your food palette eclectic and diverse in its color and taste, following a season-specific pattern.

Food groups that are excellent immuno-modulating agents

Dr. Sant further elaborated on how medicine and science have identified six food groups as immuno-modulating agents.

Mentioned below are the same along with their plant-based sources for consumption:

1. Vitamins

Vitamin A, B6, B12, C, D, E, and folates should be an essential part of your meals.

  • Vitamin A can be consumed with the help of leafy vegetables, bell peppers, spinach, carrots, and fruits like mango, papaya, and apricot.
  • Vitamin B6 promotes cellular energy extraction and can be found in soybeans, oats, bananas, and peanuts. This vitamin helps in building red blood cells, and nerve function and it prevents the accumulation of homocysteine. "However, so far, there is no evidence to confirm the adequacy of vitamin B12 from vegan sources. So, the easiest way to prevent vitamin B12 deficiency in strict vegan people is to take a vitamin B12 supplement, usually, 50 to 150 micrograms a day, or 500 to 1,000 micrograms a week," suggests Dr. Sant.
  • Foods such as oranges, strawberries, blackcurrants, broccoli, Brussel sprouts, and peppers are high in Vitamin C. Sunlight is the primary source of Vitamin D and everyone must be exposed to it every day.
  • Vitamin E can be found in nuts, seeds, and olive oil.
  • Lastly, for folate intake, ensure a fair intake of leafy veggies, sprouts, and beans. "One important point worth mentioning here is that folate will be destroyed when cooked at a high temperature. A well-cooked vegetable may lose folate as much as 95%. So, it would be sensible to eat it fresh," Dr. Sant explained.

2. Minerals

The first mineral to boost your immunity is zinc. Its deficiency can weaken your immunity and lead to catching infections easily.

  • Pumpkin seeds, cashews, peas, and almonds are great sources of zinc.
  • The second mineral is selenium which is rich in antioxidants and can be found in Brazil nuts, chia seeds, flax seeds, coconuts, whole wheat flour, garlic, and cashews. These foods regulate excessive inflammation in your body.
  • Lastly, copper too is an important nutrient for your body and can be consumed through whole wheat bread, peanuts, and other nuts like walnuts, cashews, beans, and seeds including oats, mushrooms, and spinach.

3. Omega-3 Fatty Acids

Known to improve blood oxygenation, curb chances of organ failures, and increase mortality rates, Omega-3 fatty acids are necessary for your health.

  • They can be found in flaxseeds, chia seeds, seaweeds, walnuts, kidney beans, edamame beans, and hemp seeds.
  • The other three categories of nutrients are phytochemicals, antioxidants, and probiotics which can more or less be found in all the foods listed above. Probiotics means the good bacteria found in certain foods that prompt the body's immune reaction. Usually, good bacteria or probiotics are found in yogurt, kefir, and sauerkraut.

4. Sleep and immunity

Dr. Sant emphasized that it's not only a good diet that forms a strong immune system. "It is a combination of good sleep, exercise, healthy eating habits, and great mental health that ensure improved immunity. Lack of sleep can lead to obesity and increase the risks of respiratory diseases," he stated.

He used a study to highlight meat consumption that is associated with poor sleep quality, which in turn reduces overall immunity function. Hence, he urged everyone to get good sleep and last, but not least, maintain good mental health. "Stress can be an indirect cause of low immunity. Long-term or chronic stress can destroy your immunity and also induce low-grade chronic inflammation," he added.

Read more : Do Slightly Angry Men Really Have Better Immune Systems?


Dr. Sant rounded up the session with a few pearls of wisdom. "It is vital that we manage our stress before it gets out of control, follows a plant-based lifestyle, works out, and gets enough sleep for our body to be able to function the next day," he concluded.

Expert bio

Sant Chaiyodsilp MD (FCTS, FRCST, FRCFMT) is the Senior Consultant and Specialist at Check-up Center, Phyathai 2 Hospital, and Chief Wellness Coach at Mega Wellness We Care. Taking inspiration from his life journey, where he reversed his ischemic heart condition with a plant-based whole food diet and minus any kind of surgeries, the heart surgeon-turned-family physician promotes the idea that heart disease can be reversed with a plant-based whole food diet. As a surgeon, he has treated patients in Greenland Hospital, Auckland, New Zealand, and Saraburi Regional Hospital, Saraburi, Thailand, before joining Rachavithi Hospital, Bangkok, Thailand in 1993. He served as the Director of Phyathai Heart Center, Phyathai 2 Hospital, Bangkok in 1999 and became the Executive Director at the same hospital in 2002. He was the Director and Executive Director at Kasemrad Hospital, Bangkok, Thailand.

Currently, he is the President of The Thai Resuscitation Foundation, and a Council Member of The Thai Resuscitation Foundation (Thai Heart Association). He also has a personal blog to answer health questions, which has at least two million followers per year. Most of the doctor's free time is spent on farming, gardening, and growing vegetables, which is what makes the Doctor happy because he is close to nature.


Dr. Sant Chaiyodsilp

Sant Chaiyodsilp MD (FCTS, FRCST, FRCFMT) is the Senior Consultant and Specialist at Check-up Center, Phyathai 2 Hospital and Chief Wellness Coach at Mega Wellness We Care. Taking inspiration from his own life journey, where he reversed his own ischemic heart condition with a plant-based while food diet and minus any kind of surgeries, the heart surgeon-turned-family physician promotes the idea that heart disease can be reversed with a plant-based whole food diet. As a surgeon, he has treated patients in Greenland Hospital, Auckland, New Zealand and Saraburi Regional Hospital, Saraburi, Thailand, before joining Rachavithi Hospital, Bangkok, Thailand in 1993. He served as the Director of Phyathai Heart Center, Phyathai 2 Hospital, Bangkok in 1999 and became the Executive Director at the same hospital in 2002. He was the Director and Executive Director at Kasemrad Hospital, Bangkok, Thailand.

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