Chlorella May Help Preserve Immune Function During High Intensity Athletic Training

Sedentary women who start walking briskly on a treadmill for 45 minutes a day for a few months may cut their risk of upper respiratory tract infections in half. How exactly does exercise improve our immune system?

Approximately 95 percent of all infections are initiated at the mucosal surfaces—the moist surfaces, like our eyes, nose, and mouth. These are protected by antibodies like IgA, which provide “an immunological barrier by neutralizing and preventing viral pathogens from penetrating the body through the mucosal surfaces.” The IgA in our saliva, for example, is “the first line of defense against respiratory tract infections such as pneumonia and influenza.” As you can see in my video Preserving Athlete Immunity with Chlorella, moderate aerobic exercise—even just 30 minutes in the gym three times a week—may be all it takes to significantly boost IgA levels and significantly decrease the risk of coming down with flu-like symptoms.

We’ve known for a long time that prolonged heavy exercise, though, may reduce resistance to infectious disease, manifested by an apparent two- to six-fold increase in upper respiratory tract infection symptoms for several weeks following marathon running.

Sport coaches are advised to monitor immune function, since illness could ultimately lead to a decrease in performance. Therefore, it may be necessary to take protective actions to minimize contact with cold viruses, for example. Athletes can’t get away with just washing their hands and wearing a mask, though, because upper respiratory tract infections are often triggered by reactivations of latent viruses already inside our bodies, such as Epstein-Barr virus (EBV). As soon as our immune function dips, the virus becomes reactivated. Researchers found that IgA levels drop the day before EBV comes out of hiding and causes a spike in symptoms. “These results suggest that the appearance of [upper respiratory symptoms] is associated with reactivation of EBV and reduction of [salivary] IgA during training.”

How can we preserve immunity in athletes? In Preserving Immune Function in Athletes with Nutritional Yeast, I discussed the efficacy of using a one-celled fungi—nutritional yeast—to boost the immune systems of athletes. What about a one-celled plant?

Researchers in Japan found that IgA concentrations in breast milk could be increased by giving mothers chlorella, a unicellular, freshwater, green algae sold as powder or compressed into tablets. What about other parts of the body? Thirty tablets of chlorella a day for a month increased IgA secretion in the mouth, too. But does that actually help in a clinically meaningful way? Researchers in Canada tried to see if they could boost the efficacy of flu shots, but a chlorella-derived dietary supplement did not appear to have any effect. They were using some purified extract of chlorella, though, not the real thing.

What about giving it to athletes during training camp? High-intensity physical activity and group living create an environment ripe for infection, and, indeed, the training was so intense IgA levels significantly dropped—but not in those given chlorella each day. So, chlorella intake may attenuate the reduced IgA secretion during athletic training.


There is a caveat to the use of chlorella. See Treating Hepatitis C with Chlorella and Is Chlorella Good for You? to make up your own mind about whether the benefits outweigh the risks.

Interested in some other ways to decrease your risk of upper respiratory tract infections? See:

For the cuddliest way to protect your immune function, see my Are Cats or Dogs More Protective For Children’s Health? video.

What else can exercise do? See:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

What to Take After Surgery

Medicine is messy. One of reasons researchers experiment on animals is they can create uniform, standardized injuries to test potential remedies. It’s not like you can just cut open 50 people and see if something works better than a sugar pill. But, wait a second, we cut people open all the time. It’s called surgery.

In my video Speeding Recovery from Surgery with Turmeric, I discuss a double-blind, randomized, placebo-controlled study that investigated the efficacy of turmeric curcumin in pain and post-operative fatigue in patients who had their gall bladders removed. Fifty people were cut into and given either curcumin or an identical-looking placebo, along with rescue analgesics—i.e., actual painkillers to take if the pain became unbearable. Even though it’s just laparoscopic surgery, people don’t realize what a toll it can take. (You can be out of commission for a month!) In India, turmeric—found in curry powder—has traditionally been used as a remedy for traumatic pain and fatigue, so the researchers decided to put it to the test.

According to the study, in the weeks following surgery, there was a dramatic drop in pain and fatigue scores in the turmeric curcumin group, with p-values of 0.000. Those are my kind of p-values! The “p-value” refers to a measure of the strength of evidence. The smaller it is, the stronger the evidence is that the result they found didn’t just happen by chance. By convention, a p-value under 0.05 is considered small enough for a result to be considered statistically significant. This means that you’d only expect to find a result that remarkable simply by coincidence 5% of the time, or in 1 out of 20 cases. So a p-value like the one in the study, <0.000, suggests you’d have to run the experiment thousands of times before you’d come up with such a dramatic result just by chance.

It’s hard to come up with objective measures of pain and fatigue, but drug-wise, the curcumin group was still in so much pain they were forced to take 7 of the rescue painkillers. In the same time period, though, the control group had to take 39 pain pills. Of course, it’s better not to get gallstones in the first place, which you can learn more about in my video Cholesterol Gallstones, but the researchers’ conclusion was like no other I’ve ever read in a drug trial.

“Turmeric is a natural food ingredient, palatable, and harmless.” Okay, so far so good. It continued: “It proves to be beneficial as it may be an ecofriendly alternative to synthesized anti-inflammatory drugs which have a definite carbon footprint due to industrial production.” Since when do surgery journals care about the greenhouse gas emissions from drug companies? I just had to look up the reference in the journal Surgical Endoscopy entitled “Journey of the Carbon-Literate and Climate-Conscious Endosurgeon Having a Head, Heart, Hands, And Holistic Sense Of Responsibdlity.” I don’t know what’s stranger, seeing the word “holistic” in a surgical journal or the name of this guy’s practice: “Dr. Agarwal’s Surgery & Yoga.”


The benefits of turmeric are clear—and not just as a remedy for pain. The spice also serves as a potent treatment against cancer, as I explain in these videos:

Turmeric is effective at fighting many other health conditions, too, as is evident in these videos:

Finally, you may be wondering whether turmeric is best taken as a supplement or in whole food form. I invite you to watch Turmeric or Curcumin: Plants vs. Pills and find out.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Boosting Moods with Foods

In my video Plant-Based Diets for Improved Mood and Productivity, I discuss a recent systematic review and meta-analysis of dietary patterns and depression that concluded that a healthy diet pattern was “significantly associated with a reduced odds of depression.” However, out of the 21 studies the researchers were able to find in the medical literature, they were only able to find one randomized controlled trial, the study design that provides the highest level of evidence. It was the study I profiled in my Improving Mood Through Diet video, in which removing meat (including fish and poultry) and eggs improved several mood scores in just two weeks.

We’ve known those eating plant-based diets tend to have healthier mood states—less tension, anxiety, depression, anger, hostility, and fatigue—but we couldn’t tell if it was cause and effect until it was put to the test, which researchers finally did. What could account for such rapid results?

Eating a vegetarian diet gives you a better antioxidant status, which may help with depression, as I discussed in Antioxidants and Depression. Also, as I previously addressed in A Better Way to Boost Serotonin, consumption of even a single carbohydrate-rich meal can improve depression, tension, anger, confusion, sadness, fatigue, alertness, and calmness scores among patients with premenstrual syndrome. But what about long term?

Overweight men and women were randomized into two groups: one following a low-carb, high-fat diet and the other following a high-carb, low-fat diet for a year. By the end of the study, who had less depression, anxiety, anger, hostility, feelings of dejection, tension, fatigue, confusion, fewer mood disturbances, and better vigor? “The sustained improvements in mood in the LF [low-fat] group compared with the LC [low-carb] group are consistent with results from epidemiological studies showing that diets high in carbohydrate and low in fat and protein are associated with lower levels of anxiety and depression and have beneficial effects on psychological well-being.”

The overall amount of fat in the research subjects’ diet didn’t change significantly, though. But the type of fat did. Their arachidonic acid intake fell to zero. Arachidonic acid is an inflammatory omega-6 fatty acid that can adversely affect mental health via a “cascade of neuroinflammation”—that is, it may inflame your brain. High levels of arachidonic acid in the bloodstream have been associated with a greater likelihood of suicidal risk and major depressive episodes, for example. How can we stay away from the stuff? Americans are exposed to arachidonic acid primarily through chicken and eggs. So, when we remove eggs, chicken, and other meat we eliminate preformed arachidonic acid from our diet.

Although high-quality treatment studies examining diet’s impact on depression are scarce, there was the successful two-week trial discussed earlier and, even better, a twenty-two-week study. Overweight or diabetic employees of a major insurance corporation received either weekly group instruction on a whole food, plant-based diet or no diet instruction for five and one-half months. There was no portion size restriction, no calorie counting, no carb counting, and no change in exercise. No meals were provided, but the company cafeteria did start offering daily plant-based options such as lentil soup, minestrone, and bean burritos.

Participants ate no meat, eggs, dairy, oil, or junk, yet they reported greater diet satisfaction compared with the control group participants who had no diet restrictions. More participants in the plant-based intervention group reported improved digestion, increased energy, and better sleep than usual at week 22 compared with the control group. They also reported a significant improvement in physical functioning, general health, vitality, and mental health. The plant-based group beat out controls on nearly every measure.

There were also significant improvements in work productivity, thought to be due in large part to their improvements in health. What this study demonstrated is that a cholesterol-free diet is acceptable, not only in research settings but also in a typical corporate environment, improving quality of life and productivity at little cost. All we needed was a large, controlled trial for confirmation, but we didn’t have such a thing… until now.

A study of ten corporate sites across the country from San Diego, California, to Macon, Georgia, with the same set-up as before found that a plant-based nutrition program in a multi-center, corporate setting improves depression, anxiety, and productivity. Significant improvements were found in depression, anxiety, fatigue, emotional well-being, and daily functioning. “Lifestyle interventions have an increasingly apparent role in physical and mental health, and among the most effective of these is the use of plant-based diets.”


The pilot data on workplace interventions can be found in my videos Slimming the Gecko and Plant-Based Workplace Intervention.

Diet can help at home, too. See:

And, for background on the inflammatory fatty acid arachidonic acid, see my videos Inflammatory Remarks About Arachidonic Acid, Chicken, Eggs, and Inflammation, and Chicken’s Fate Is Sealed.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: