There had been a LOT of hype in recent times due to the coronavirus outbreak on the links between nutrition, health & immune function. A lot of this information has been poorly supported by evidence, misleading or simply false. Such claims include ketogenic diets preventing you from catching COVID, or certain supplements boosting your immune system.
Let’s just clarify something before we get into this, there is essentially nothing you can do to prevent you from catching a virus, the healthiest people in the world can get a virus, if your immune system is in proper order, you will have a better chance of fending off the virus, or simply experiencing milder symptoms. In individuals who are immunocompromised or with underlying illnesses, the ability of the innate immune system is not as strong as it is in normal healthy adults. So to clear the nuance, you can be immunocompromised or have immune dampening, for a variety of reasons, but you CANNOT boost your immune system or have a supercharged one. It’s not like a see saw.
So, what are some things you can do maintain a normal healthy immune system?
1. Eat adequate calories, especially if you are active and exercising. Depleted glycogen stores can dampen immunity and exaggerate stress response to exercise. Excess weight loss or prolonged hypocaloric dieting can result in decreased white blood cell production. A good rule of thumb would be 45kcal/kg/day.
2. Eat your protein. Remember, protein is the material for everything in your body, you need protein to build white blood cells. Loss of muscle mass in clinical scenarios results in increased susceptibility to infection, poorer recovery and decreased ability to fight illness. To note, this level of muscle loss is not typically seen in normal adults, this is more appropriate for elderly or ill folks, who may have mobility issues, or difficultly swallowing food, so make sure your elderly or more vulnerable relatives do get a good source of protein. Nutrient reference values are 0.6-0.8g/kg/day for normal healthy adults.
3. Drink up. Mucosal secretions are one of the first barriers of defence in illness. Staying hydrated will help keep mucus thin and easier to shift. Thick mucus congealing sinuses or in airways can help infection spread and worsen. 35ml/kg/day will keep your sinuses happy.
4. Eat your fruit, veg & nuts. Superfoods aren’t real, but you do need micronutrients and vitamins for proper immune function, and certain antioxidants will help immune function. Hit your 5 a day, aiming to get 5 different colours, a portion of veg is approx 80g, or a handful. The most important vitamins and minerals are vitamin D, C, Iron & Zinc. A handful of nuts will help this, they are like nature’s little multivitamins.
5. Sleep adequately and regularly. Get your 7-8 hours a night, try cut out the phone or screens beforehand, limit caffeine about 6hrs pre bed. Poor sleep makes you less resilient to everything.
6. Stay active and exercise moderately, this helps keep your immune system ticking over – intense exercise and overtraining will do the opposite, exercise has a hormetic zone in terms of beneficial immunity & health effects. WHO recommends 30mins/day of moderate activity.