For your immune system to work properly to protect you from all types of infections, it needs a variety of nutrients from your foods. Good digestion and gut function is important too, which will be a topic for another article in the future!
All those people who have hoarded high carbohydrate foods for the coronavirus apocalypse may not like what I am about to say!
A very recent published open letter from several doctors and specialists trained in nutritional medicine (Clemens et al., 2020) has again confirmed that diets high in carbohydrates, in particular the refined carbohydrates of sugary foods and drinks, grain-based foods (breads, bakery products, cereals, pasta etc) and alcohol (sorry!), all deplete the immune system in a couple of ways:
- Carbohydrate-rich foods are metabolised in your body into glucose, which causes an increase in blood sugar levels. High blood sugar levels cause a lot of inflammation, particularly to the blood vessels, the liver, but many other organs and tissues too
- High carbohydrate foods are generally low in real nutrients, thus causing nutrient deficiencies if consumed in high amounts
- High carbohydrate diets cause an increased demand for certain nutrients needed to metabolise the sugar from the foods, such as vitamin C, zinc, magnesium, B-vitamins and more. Note that some of these I've mentioned before in my previous articles on what you need to improve your immune system function
- People with chronic health conditions have been shown to have reduced levels of these essential nutrients. Generally, the elderly have more chronic health conditions than other age groups, meaning that they are at greater risk to infections (which is what we are seeing in this coronavirus infection)
- The higher your blood sugar level, the lower your vitamin C level, and vitamin C is blocked from entering cells when blood sugar levels are high
- Immune system cells (white blood cells) need 100 times the amount of vitamin C than other cells, so high blood glucose will reduce immune system function
- High levels of fructose (a type of sugar from fruit, fruit juices, soft drinks, grains and alcohol) significantly inhibits the activation of vitamin D (which is a massive immune system booster and infection protective compound).
To confirm this, other studies showed by reducing carbohydrate intake can provide protection against infections, by stimulating the immune system response (Clemens et al., 2020; Goldberg et al, 2019).
Sadly all those high carbohydrate long shelf-life foods that people have hoarded and now in short supply on the bare supermarket shelves, should be eaten at a minimum because of their negative effects on your immune system.
You need your immune system working optimally at the moment, which means eating more whole, fresh, real and preferably organic foods as much as possible. This means quality meats, vegetables , nuts and seeds, quality fats, eggs, etc and only a small amount of fruit. These foods are nutrient-dense with more real nutrients your immune system needs! Eat less of the highly processed and packaged foods, especially those high in sugar or foods that metabolise into sugar (glucose or fructose) from grain-based foods.
Clemens, Z., Tóth, C., Dabóczi, A., Andrásofszky, E., Horváth, R., Kolonics, G. (2020). Possibilities of reducing the spread of the SARS-CoV-2 virus and increasing natural resistance to the disease via nutritional intervention. Retrieved 1 April 2020 from https://www.researchgate.net/publication/340296931_Possibilities_of_reducing_the_spread_of_the_SARS-CoV-2_virus_and_increasing_natural_resistance_to_the_disease_via_nutritional_intervention. DOI: 10.13140/RG.2.2.27031.93605
Goldberg, E.L., Molony, R.D., Kudo, E., Sidorov, S., Kong, Y., Dixit, V.D., & Iwasaki. A. (2019). Ketogenic diet activates protective γδ T cell responses against influenza virus infection. Science Immunology, 4 (41): eaav2026. DOI: 10.1126/sciimmunol.aav2026