Both red and green peppers have twice the vitamin C content of oranges. Vitamin C is important for maintaining a healthy immune system
Another veg with more vitamin C than citrus fruit, kale is also a marvelous provider of vitamin A (from beta carotene) and provides antioxidant vitamin E too.
Garlic supposedly keeps away vampires but might also slightly up your odds against the common cold. Researchers assessed 146 participants who were given a garlic tablet
We need sufficient protein for the body's immune system, especially for healing and recovery according to the Academy of Nutrition and Dietetics.
Mushrooms are a decent source of selenium and B vitamins too. You can even find vitamin D-enriched mushrooms which have 2.5mg of vitamin D per 100g (3.5oz).
All nuts are nutritious but grab a mixture of cashews, brazils and peanuts, and you’ll get particularly good levels of zinc, selenium, iron and vitamin B6.
Glucose may help viral infections get better but hamper recovery from bacterial ones. Either way there’s no evidence that a modest amount of sugar
In a review of children with a cough, honey relieved symptoms better than diphenhydramine (an antihistamine cough-suppressant), no treatment and placebo.
Some kefir-specific microbes have been shown to prime the immune system against bacterial infections. A product made the time-honored way with real kefir grains is probably best.
A little cold-pressed rapeseed oil has all the heart-healthy monounsaturated fats of extra virgin olive oil, with the added benefit of a high level of the antioxidant vitamin E.