AMY PACKER
help – but avoid very prolonged workouts and endurance events as these weaken immunity. A third of marathon runners catch respiratory tract infections within a fortnight of an event, compared to one in seven noncompetitors.
They say sleep is the best medicine, and dozens of studies have underlined its importance for immunity.
When we sleep there is a rise in infection-fighting proteins called cytokines, as well as hormones and other body chemicals which repair damaged cells.
A study published last year reported that sleep makes T-cells, a type of lymphocyte, which plays a central role in the immune response, more effective more efficient at targeting and destroying viruses.
Professor Russell Foster, an expert in sleep and health, based at Oxford University advises:
“Ensure the bedroom is a place that promotes sleep. Don’t text, use a computer or watch TV for at least half an hour before trying to sleep and avoid bright lights. Try not to nap during the day, seek out natural light in the morning to adjust the body clock, and avoid drinking caffeinated drinks after your lunch.”
Vitamin C is important for immunity, but there is little evidence that highdose supplements protect against infection. The common cold is caused by respiratory viruses, and researchers who analysed 29 studies involving 11,306 people, concluded taking vitamin C supplements “is not justified”. However, they found a daily dose of 200mg of vitamin C reduces the duration of colds by 8%. As vitamin C is water soluble and cannot be stored, it should be taken as a series of frequent lower doses. High doses lead to a brief spike in blood levels before the excess is excreted via urine. A 100ml glass of fresh orange juice provides the 40mg a day recommended by the NHS, but if you are buying juice from concentrate, apple has slightly more – 49mg per 100ml, compared to 31mg in orange juice.
It’s natural to be worried about Covid19, but try not to stress because that could undermine your immune system.
Long-term stress inhibits production of blood cells called leukocytes which protect against infection. In Korea, doctors teaching Covid-19 patients muscle relaxation techniques report “significant” improvements in sleep quality.
One in 12 adults is putting immunity at risk by not getting enough zinc. The mineral, which is found in shellfish and dairy foods, has been proven to reduce the risk of infections and stall the replication of viruses.
A 2017 super-study, which looked at all published evidence, found taking zinc within 24 hours of the first symptoms reduced the duration of colds by a third.
Doses used in the trials ranged from 80mg to 207mg a day.
Echinacea is promoted as an immuneboosting remedy, however, the results of published studies are far from conclusive.
Dr Chris Etheridge, a medical herbalist and president of the College of Practitioners of Phytotherapy, says this is largely because so many different species, parts of the plant, production methods and concentrations are used.
He says: “Looking at trials, there is good evidence for Echinacea angustifolia, and preparations made from the root have shown superior results. Look for a product with a Traditional Herbal Registration so you know it is pharmaceutical grade quality.”
Dr Etheridge says there is stronger evidence for the immune-boosting properties of Pelargonium sidoides, a medicinal herb from South Africa. Kaloba, the pelargonium extract available on the high street, is listed by the National Institute for Health and Care Excellence as a safe and effective treatment for chest infections in children. Researchers at Southampton University are using the same extract in a study designed to reduce the use of antibiotics in patients with bronchitis.
Garlic has antiviral properties, but there is little evidence supplements will prevent infections. However eating lots of it is bound to help with social distancing!