Protection from Flu & Winter Virus

From the moment the children return to school in September, we start to see a steady increase in virus strains, such as flu, coughs and colds.

Of course, we can’t blame the children – although places that contain lots of tiny humans are a bit of a breeding ground for germs, there are other reasons why viruses are so prevalent in the Autumn and early winter.

Once the nights draw in and our exposure to the sun’s rays decreases, it is important to start supplementing with vitamin D. Less light and sunshine means a lack of vitamin D, which has not only been linked to an increased risk in flu and other “winter” viruses (1), but is also considered important in the prevention of certain cancers.(2)

Which is Best? D2 or D3?

There is sometimes confusion about which type of Vitamin D is best; D2 or D3?  Vitamin D2 and D3 are not equal when it comes to raising your vitamin D status. Although both are effectively absorbed into the bloodstream; the liver metabolises them differently. (3)

Vitamin D3 is at least three times as potent as vitamin D2 and is produced in the skin with sunlight exposure, making D3 superior to D2 as a Vitamin D supplement. (1)

Nature gets it right.  Seasonal fruit and vegetables help to sustain us at certain times of the year.  In the summer, we have an abundance of cooling foods, such as summer fruits and salads.  In the winter, there are large, juicy oranges; full of vitamin C to help keep the bugs at bay; and root vegetables such as onions, carrots and garlic, which contain antioxidants and vitamins – all helpful to an immune system weakened by the change in season. (4)(5)(6)

Patients ask if it really makes a difference eating fruit and vegetables when there are so many supplements available?  The answer is a resounding “YES”.  Our digestive system prefers to extract vitamins and minerals from food; it also keeps the gut healthier, which is useful in preventing winter viruses.

Strengthening the Immune System Naturally

Having a diet that contains at least 50% of seasonal foods will help your immune system; but there are other things that you can do to give it a helping hand.  Exercise may not seem particularly appealing when its cold outside, but fresh air is very helpful in supporting the immune system.  Most of us work and live in buildings with central heating and a warm environment that has little moisture – all of which is the perfect breeding ground for viruses; so, your immune system will thank you for venturing outside for a walk (7)

Stress and sleep also put a strain on the immune system; looking after poorly children, working, and the build up to Christmas put a strain on even the most organised person.  These are things that our outside of our control but can have a detrimental effect on our health as we are essentially “running on empty”, and possibly risking adrenal fatigue.

When this happens, I use herbs that are “adaptogens”, which help to strengthen our stress response, support our adrenal glands and minimise problems with the immune system (8)

As with all herbs, it is best to seek professional advice, as different adaptogens do different things and some can even be harmful if used incorrectly; such as liquorice – which is a beautiful and effective adaptogen – but can seriously affect the blood pressure in some individuals.

Herbal Remedies For Treating Flu

If, despite addressing things within your control, such as diet, stress and sleep, you still end up with the winter nasties, there are a number of herbs effective in treating flu; Elderflower, Echinacea and American Ginseng are very beneficial (9) and herbs such as Thyme or Liquorice, which are particularly indicated in the treatment of coughs or sore throats can be added by a Medical Herbalist, to ensure that you are taking the correct dosage and to produce a bespoke medicine that will support you through the winter virus months.

Jane Sanderson November 2019



  1. Schwalfenberg G. Vitamin D for influenza. Can Fam Physician [Internet]. 2015 Jun Available from:
  2. National Cancer Institute. Vitamin D and Cancer Prevention – National Cancer Institute [Internet]. 2013. Available from:
  3. Bikle DD. Vitamin D metabolism, mechanism of action, and clinical applications. Vol. 21, Chemistry and Biology. Cell Press; 2014. p. 319–29.
  4. The Self NutritionData. Carrots, raw [Includes USDA commodity food A099] Nutrition Facts & Calories [Internet]. 2018 Available from:
  5. The Self NutritionData. Garlic, raw Nutrition Facts & Calories [Internet]. 2018 Available from:
  6. The Self NutritionData. Onions, raw Nutrition Facts & Calories [Internet]. 2018 Available from:
  7. Why Is Fresh Air Important? | [Internet]. 2019. Available from:
  8. Winston D, Maimes S. Adaptogens. Healing Arts Press; 2007.
  9. Mousa HAL. Prevention and Treatment of Influenza, Influenza-Like Illness, and Common Cold by Herbal, Complementary, and Natural Therapies. J Evidence-Based Complement Altern Med. 2017 Jan 1;22(1):166–74.

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