COVID-19 is so bad! Nutritionists teach you how to improve your immunity through diet

COVID-19, which has brought the world to a standstill and is notorious for its terrifying effects, mainly affects the respiratory system. Symptoms after infection range from the common cold and mild influenza to severe pneumonia. The scary thing is that it can cause a cytokine storm (also known as an immune storm) in the body, causing the host's immune system to over-defend. This is a new virus for humans, and we do not have natural immunity to fight it, so it spreads so quickly. In the face of the aggressive virus, in addition to the strategy of "fighting the outside world", including: washing hands frequently, wearing masks, maintaining social distance, etc., we must also "maintain domestic stability" to enhance our own immunity.

When facing viruses, the body has set up layers of checkpoints to provide active and effective defense. First is the three-in-one barrier, including the skin and mucous membranes, the gastrointestinal tract, respiratory tract, urogenital tract (physical), or the stomach providing an acidic pH environment (chemical), and commensal organisms in the skin and intestines, secretions of IgA and antimicrobial proteins in saliva and tears, and the complement system (biological), which prevent pathogens from entering the body. Once the pathogen breaks through the barrier and enters the body, the innate immune cell recognition system will be activated, such as macrophages, monocytes and dendritic cells, which will identify the pathogen and eliminate it, finally producing immune memory. Vaccination is the production of immune memory. However, as we age, the thymus gland produces fewer naive T lymphocytes, resulting in a decreased ability to cope with antigens, known as immunosenescence. This is one of the reasons why the symptoms of COVID-19 are more severe in the elderly.

Avoiding the harm of viruses and strengthening immunity are the basis of self-protection

The three major methods of "pacifying the country" cannot be abandoned

1. Maintain a healthy body position and don’t get into trouble with the virus

Based on the 2009 H1N1 influenza A virus pandemic, studies have found that obese people have a delayed and weakened response to the virus after infection, and their ability to recover after becoming ill is also poorer. For patients with COVID-19, a French study found that the incidence of infection requiring ventilator treatment (severe cases) was significantly higher in obese patients than in non-obese patients (85.7% vs 47.1%).

Healthy body position: BMI 18.5~23.9 (BMI calculation formula: weight (kg)/height 2 (m2)

2. Sufficient micronutrients, sufficient strength

Immune response requires cell proliferation. In addition to taking in enough calories and protein, more attention should be paid to vitamins and minerals, which are also important cofactors in the metabolic synthesis process.

Vitamin A

It helps epithelial tissue differentiate normally and maintains the integrity of the first-line physical barrier; it also plays an important role in the maturation and functional integrity of immune cells. Studies have found that vitamin A supplementation in children can reduce mortality from the disease and improve symptoms of acute pneumonia. The general intake of vitamin A in China is sufficient. If you need to use additional supplements, be careful not to exceed 3,000 micrograms per day!

Vitamin B complex

Participates in intestinal immune regulation and helps intestinal barrier function. Studies have shown that a lack of folic acid and vitamin B6 can cause atrophy of the thymus and spleen and reduce the production of T lymphocytes. Vitamin B12 deficiency can reduce the capacity of immune cells. B vitamins are widely found in six major food groups, and a balanced diet can ensure adequate intake. It is particularly important to note that vegetarians are more likely to be deficient in vitamin B12, so they may consider additional supplementation. 2.4 micrograms per day.

Vitamin C

Essential nutrients for collagen synthesis, maintaining the integrity of epithelial cells. Studies have found that if healthy adults lack vitamin C in their diet, the concentration of vitamin C in the body's monocytes will decrease by 50%, which will relatively reduce the immune response to antigens. In addition, for people who are under physiological stress (such as colds), vitamin C supplementation can reduce the severity and duration of respiratory infections.

(Photo courtesy of Cathay Hospital)

Vitamin D

It enhances epithelial cell integrity and induces the synthesis of antimicrobial peptides, epithelial cells and macrophages, directly enhancing the host's defense capabilities. The results of British studies and the third National Health and Nutrition Examination Survey (NHANES) of the United States both showed that serum vitamin D and respiratory tract infections were negatively correlated. There are few food sources of vitamin D, and the general public does not consume enough of it. For people who have less sunlight, it is recommended that they take supplements, 400 IU per day, but not more than 2000 IU/day.

Vitamin E

Studies have found that high-dose vitamin E supplementation can enhance T helper cell immunity and improve vaccination response, as well as reduce the risk of upper respiratory tract infections. The intake of calcium by Chinese people is generally insufficient, especially girls. Vitamin E mainly comes from vegetable oils and nuts.

(Photo courtesy of Cathay Hospital)

3. Good intestinal bacteria and probiotics

Abnormalities in the gut flora are called dysbiosis and are associated with obesity and age. The study found that Chinese COVID-19 patients had dysbiosis in the intestinal flora (reduced numbers of Lactobacillus and Bifidobacterium). All current research evidence suggests that Lactobacillus and Bifidobacterium may improve immune function, enhance the response to seasonal influenza vaccination (which mimics viral infection), and reduce the incidence of respiratory tract infections.

Based on healthy eating guidelines and increasing the variety of food choices, this is the most suitable diet pattern for supporting the immune system. Probiotics, especially Lactobacillus and Bifidobacterium, can change the microbiota, modulate immune responses and reduce the chance of infection.