It’s not just age, weight, and health conditions that put people at higher risk for Covid-19, it’s compromised nutritional status. Here’s the less-talked role nutrition plays in the pandemic and what desperately needs to change.
As a seasoned dietitian, I’m used to others viewing nutrition as an afterthought. Whether it’s the doctor who tried everything with his patient only to call me in as a last resort or the corporate project that went on for months before marketing thought to bring me in, nutrition is often filed away as nice, but not necessary.
I’ve seen this happen with the pandemic too. Everyone talks about vaccines, drugs, lockdowns, and wearing masks, but not much about the importance of nutrition in building and maintaining a robust immune system.
Yet there’s no denying the pandemic has shed a very bright light on nutrition. And this light tells us that an overwhelming number of Americans have comprised nutritional status putting them at higher risk of severe disease from Covid-19. Even more disturbing is that we are doing very little about it.
Nutrition is vital for a strong immune system
Vitamins and minerals, also known as micronutrients, expedite many of the body’s physiologic and metabolic processes. Whether it’s the development of the body’s first line of defense (the innate immune system), growth and differentiation of immune cells, the production of antibodies and memory cells, or decreasing inflammation, they are necessary for a robust immune system.
Research shows that a dozen or so key nutrients support immune function against viruses including vitamins A, C, D, E, B6, B12, and folate, iron, magnesium, and trace elements including zinc, selenium, and copper and omega-3 fatty acids.
Most people don’t have outright nutrition deficiencies which are when symptoms are noticeable. Instead, they have what is referred to as subclinical nutrition deficiencies meaning they have enough of a vitamin or mineral to function, but the amount in blood and tissue drops. And when a novel virus like the Coronavirus hits, the body has no reserves to fight it effectively.
“The covid pandemic simply unmasked what we already know about the health status of our country,” said Jeffrey B. Blumberg, Professor Emeritus at the Friedman School of Nutrition Science and Policy at Tufts University in Boston. “We are very poorly nourished”
Blumberg explains that most Americans are not even close to meeting dietary recommendations with a score on the Healthy Eating Index of 59 out of 100. According to National Health and Nutrition Examination Survey Data (NHANES), 97% of Americans are not getting the recommended amount of potassium, 90% are not getting the recommended amount of vitamin D, choline, and vitamin E. “And when we look at other nutrients like magnesium, calcium, vitamin A and vitamin C, it’s a shocking prevalence of inadequate intakes,” he said.
Studies on nutrition and Covid-19
When it comes to micronutrients, vitamin D has received the most attention due to its ability to reduce the pro-inflammatory TH1 cytokines.
Early in the pandemic, Gareth Davies, BSC, Ph.D. along with Dr. Attila Garami and Dr. Joanna Byers wrote and circulated three documents summarizing the evidence for vitamin D in respiratory illness, recommending physicians test, treat, and measure vitamin D. The documents went viral.
They followed up with a paper using techniques from physics and AI to present formal analytical proof that vitamin D deficiency causes poor outcomes in Covid-19. Since then, even though a majority of research in favor of a positive effect of vitamin D on Covid-19 outcomes and prevention, nothing has materialized from it.
“I could see plainly what was happening in the data. It was as clear as seeing a colour in a black and white photo,” Davies said. “I couldn’t understand why other people didn’t see it.”
Davies felt so strongly he co-organized an international Open Letter to all world governments calling for action to use vitamin D against the pandemic. It’s been signed by 220 scientists and doctors and it’s been endorsed by a former US surgeon general.
Read: Can Vitamin D Protect us From Covid-19?
Research has also linked low levels of iron, zinc, omega-3 fatty acids, and selenium with more severe disease and mortality from Covid-19. It has been suggested that the loss of taste (ageusia) and smell (anosmia), key symptoms of Covid-19, may be related to marginal zinc status. After all, zinc declines 60% with viral illnesses and anosmia and ageusia are deficiency symptoms.
A study revealed that European countries hit the hardest by Covid-19, were more likely to have suboptimal intake of vitamins D, A, and B12. Another study with Covid-19 patients found that 76% were vitamin D deficient and 42% were selenium deficient.
Pooling all the studies together, a meta-analysis in Nutrients found that the absence of micronutrient deficiencies decreased the odds of getting Covid-19. It also lessened the chance of severe disease for those who became infected.
Could Long Covid be related to nutrient deficiencies?
There’s Covid-19 and then there’s “Long Covid” which is when symptoms linger for weeks or months after infection. The medical term is Post-Acute Sequelae of SARS-CoV-2 infection (PASC). These symptoms include fatigue, high heart rate, sleep problems, gastrointestinal issues, dizziness, loss of taste and smell, brain fog, and anxiety/depression.
Even though many of the symptoms of long covid are similar to nutrient deficiencies, there’s scant research on the subject.
In one study, Covid-19 patients with a loss smell recovered from anosmia quicker when given zinc therapy (7 days vs. 18 days). And a case report of a 42-year-old woman with a mild case of Covid-19 followed by lingering symptoms of fatigue, dizziness, and depression was found to be vitamin B-12 deficient.
Half of 19 patients who were still experiencing symptoms a median of 47 days after infection were found to be vitamin D deficient and 21% anemic. Most of the anemia was due to iron but one case was due to iron and B12. Another study showed 60 days after infection, 30 percent of patients were iron deficient. Iron deficiency with or without anemia causes fatigue, the most common symptom of Long Covid (see chart for symptoms below).
Could most people with lasting Covid-19 symptoms have nutrient deficiencies? After all, viral illnesses tend to deplete levels of micronutrients that may have been borderline or low to begin with.
Yet there’s no mention of nutrition and Long Covid in the research or proposed treatment plans. An NIH workshop held on this very topic to identify gaps in knowledge did not even mention nutrition as a potential factor.
High-risk populations = high nutrition risk
The same populations who are at higher risk for Covid-19 severity are also at higher risk for poor nutrition status. In a study with 182 Covid-19 patients over 65, 52.7% were found to be “malnourished” and 27.5% were “at risk of malnutrition.” It is estimated that as many as 38% of older adults have a vitamin B12 deficiency, with age being the biggest risk factor.
Although people with health conditions are known to have lower levels of vitamin D, they are also at higher nutritional risk due to medication use. In fact, the second most prescribed drug, the antihypertensive drug ace inhibitors, has been shown to decrease zinc status.
Metformin frequently prescribed for diabetes increases the risk of calcium, vitamin D, and vitamin B12 deficiencies. According to a U.S. services study, 22% of outpatient diabetes patients had vitamin B12 deficiency.
The seventh most prescribed medication, proton pump inhibitors, interferes with the absorption of vitamin B12, vitamin C, iron, magnesium, zinc, and beta carotene through neutralizing stomach acid.
People with darker skin and higher weights, also at higher risk of Covid-19 severity, are more likely to be vitamin D deficient. Most Americans – about 80% — have vitamin D levels above 20ng/ml according to 2011-2014 NHANES data. But when separated by race less than 50% of blacks did, 63% of Asians, 68% of Hispanics, and 86% white.
Heavier people are not only more likely to be deficient in vitamin D they need 2-3 times more to reach optimal levels.
Why aren’t we catching nutrition shortfalls?
Unfortunately, our healthcare system is not set up to catch nutrition shortfalls. Medical students in the US get an average of 14 hours of nutrition training according to a 2015 study in the Journal of Biomedical Education. A more recent review in The Lancet Planetary Health showed this is a challenge in other countries as well. The researchers write:
Collectively, it is clear that despite the centrality of nutrition to a healthy lifestyle, graduating medical students are not supported through their education to provide high-quality, effective nutrition care to patients—a situation that has gone on for too long.
Another factor is that doctor visits provide minimal nutrition-related blood testing. Screening often includes a complete blood count (CBC), a lipid panel checking for heart disease risk factors, and diabetes markers like fasting glucose. The only nutrient deficiency this screens for is anemia through the CBC. Anemia whether it’s caused by iron, B12, or folate is a late stage of deficiency.
To give you an example, I was diagnosed with iron deficiency anemia a few years back and realized I had been low on iron for years. I attributed my fatigue to being a busy mom. Ferritin is a more sensitive marker of iron status and can catch deficiency earlier so why didn’t they measure that?
After the age of 60, people are at higher risk for B12 deficiency due to changes in stomach acid affecting absorption, yet insurance only covers this test in those 75 or older based on age alone.
Even though doctors are encouraged to periodically screen for vitamin B12 in patients on metformin, no formal screening recommendations exist. One study showed that less than half of metformin patients are tested for B12. Nothing has been done about this even though annual screening was recommended 50 years ago.
And while some doctors screen for vitamin D, many don’t. In fact, the United States Preventative Services Task Force (USPSTF) recently came out saying there’s insufficient evidence to screen people for vitamin D without symptoms.
Really?
Blumberg explains that the USPSTF focused on vitamin D’s effect on conditions like heart disease, cancer, and osteoporosis. “They didn’t ask what’s your susceptibility to the common cold, the coronavirus — are you working at a level to maintain a robust immune response?”
Nutrition research challenges
Next is the issue of nutrition research and how little is being done. The National Institutes of Health sets aside a meager five percent of its budget for nutrition research. Additionally, the gold standard of research, randomized control trials (RCTs) heavily relied on for drugs may not always give us the full picture of nutrition’s impact.
“In the vitamin D studies, in the omega-3 studies, they almost never measure baseline levels,” said Blumberg. “what if we did that for drugs like anti-hypertensives but didn’t measure blood pressure at the beginning of the study. In studies, some people are insufficient and sufficient in both groups. That’s one of the key challenges with RCTs and why they often don’t answer the questions we were really asking.”
Another key difference is prevention is not the same as treatment. So, having optimal levels of vitamin D may help prevent infection or the severity of infection but not work in the short term as a treatment. One study in Nutrients with frail elderly Covid-19 patients showed that those supplemented with vitamin D the preceding year had a 93% survival rate after 14 days, compared to 81.2% of those supplemented after infection and 68.7% in those without any supplementation at all.
As a modern society, we’ve made progress in the areas we’ve invested in such as technology, drugs, and new medical treatments. But we’ve virtually stood still when it comes to progress on nutrition.
“Part of the sorry state we find ourselves in today is because we have not invested in public health, we have not invested in nutrition,” said Blumberg.
A step in the right direction
It’s not all bad news. Last August Griffin Rodgers and Francis Collins from the NIH wrote a piece in the Journal of American Medical Association promising an investment of $150 million from the common fund in what they call “precision nutrition.” Blumberg explains that this approach will try to answer the question of why some people respond to nutrition interventions and others don’t – is it their genome, microbiome, or metabolism?
“In their strategic plan 2020-2030, they have one very interesting statement: precision nutrition for all!” he pointed out. “They didn’t put it in a medical model context where you need to see your physician and maybe they’ll do these diagnostics.”
Taking it a giant step further, Blumberg and his colleagues are calling for a National Institute of Nutrition which would require a significant investment. “After all, we have a National Institute of Diabetes and Digestive and Kidney Diseases and a National Heart, Lung, and Blood Institute, why not nutrition?” he said. “It could focus on the full range of nutrition, from molecular and biochemical nutrition through evidence-based nutrition practices and policies.”
A white paper published in the American Journal of Nutrition details all the areas a federal agency focused on nutrition could address from Food as Medicine to Health Equity to Federal Investments to Precision Nutrition.
It’s time for action: nutrition is necessary!
As vaccination rates climb, the pandemic is winding down. But we can’t forget the nutrition lesson.
We shouldn’t have to fight to get simple blood tests done that can help us figure out if our bodies are getting what they need. And we need much more research to understand how nutrition relates to optimal functioning including the immune system and prevention of disease.
Enough is enough. We all need to demand nutrition catch up with the 21st century.
Imagine the day you go to your doctor and automatically get a personalized nutritional analysis and perhaps get advice from a dietitian. Blumberg adds: “Your doctor should be running your vitamin D and others for your sex and your age and certain lifestyle factors, a certain panel of nutrients you should be tested for – that’s personalized nutrition.”
Critics will say we can’t afford a proactive approach, but don’t we end up paying much more in the long run? It’s estimated that 85% of healthcare costs are related to nutrition-related chronic diseases.
“I think it’s coming,” said Blumberg about changes to nutrition. “Maybe if it happened 15 years ago on the scale that it deserved our state of metabolic health would not be so poor and the Covid-19 crisis wouldn’t have been quite so horrific.”
If the pandemic taught us anything it’s that we need to solve our nutrition crisis. That is, before the next novel virus hits.
For more on my interview with Jeffrey Blumberg, check out my latest podcast
Duration: 51:27
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