Dr Marilyn Glenville on how to support your immune system over the winter

We are really excited to introduce our guest author Dr Marilyn Glenville PhD who has written an article on how to prepare for winter health.

Dr Marilyn Glenville PhD is the UK’s leading nutritionist specialising in women’s health. She is the Former President of the Food and Health Forum at the Royal Society of Medicine and the author of a number of internationally bestselling books including ‘The Natural Health Bible for Women’. 

Read what she has to say...

How to support your immune system over the winter 

    Your immune system is your body’s in-built defence system against infection and illness. Every day you are exposed to substances that could affect your health including bacteria and viruses and your body needs to be able to recognise these as foreign and destroy them and this the role of the immune system. 

Many factors can lower your immune function including poor nutrition, being overweight, lack of exercise, too much alcohol and also smoking.

We are living in very unusual times and our sense of what is normal is changing day to day.  That can make you feel very stressed and anxious because what is happening in the world now is out of your control. The most important impact stress can have on your health is that it can weaken your immune function. This can leave you more vulnerable to getting an infection and your body’s ability to recover quickly may be compromised.

Not getting enough sleep can also lower your immune health. It is easy to think of sleep as a luxury and that we can fit more things in by cutting back on sleep. But getting quality rest and recuperation is important to keep your body and your immune system healthy. 

Poor nutrition is a major factor in low immunity. This can come from poor dietary intake particularly if your diet is low in fresh fruit and vegetables and too much alcohol and refined sugar which depletes key immune supporting nutrients like zinc and vitamin C.

Eat a diet full of fresh, seasonal ingredients and include an abundance of dark green leafy vegetables and bright colours including beetroot, berries, butternut squash and tomatoes. These contain immune supporting antioxidants like beta carotene and vitamin E. Nuts and seeds and whole grains (brown rice not white) are rich in zinc which helps increase the immune supporting effects.

Make sure that you are drinking plenty of water and limit caffeine and alcohol which all deplete zinc and magnesium. Herbal teas would be good substitutes if you usually drink a lot of caffeine.  Plenty of oats, barley and mushrooms are helpful as they contain beta-glucans which have a positive effect on your immune system. 

Also, remember that your digestive tract is the largest immune barrier in your body and probiotics can be your secret weapon for immune health. 70% of your immune system is in your gut so having good levels of beneficial bacteria are crucial. 

Nutrients to support your immune health

There are certain nutrients which are especially helpful over the winter months and for your immune health.

Vitamin C

This is the nutrient that often comes to mind first when we think of immune function and for a good reason.  Vitamin C is essential to the health of immune cells and research has shown that good levels of vitamin C can help to reduce the length of time you might suffer from an infection. Unlike most animals (but like apes and guinea pigs), we can’t manufacture vitamin C in our bodies – it has to come from food or from supplementation. Take vitamin C in the alkaline form of magnesium ascorbate as this is much gentler on the digestive system than the acidic form of vitamin C, ascorbic acid.


Zinc is another nutrient that springs to mind when thinking of supporting the immune system. It is an essential mineral which means that it cannot be made in your body and like vitamin C has to come in from the food or in supplement form. Zinc is needed by every cell in your body and affects your immune system in many ways. Research has shown that zinc deficient people can have increased susceptibility to a variety of pathogens. 


Your digestive system contains billions of bacteria and you need good levels of beneficial bacteria to help to keep control of pathogenic bacteria, parasites and yeasts. Also, for older people a probiotic could be even more important as the natural levels of these beneficial bacteria fall as we get older.

 Vitamin D

Vitamin D in an immune modulator, it can bring it up if the immune function is low and bring it down if overactive. The body does not expect to get much vitamin D from food as it is made by the exposure of your skin to sunlight, so during the winter months your level can be low. That is why the Government recommend that all adults and children over one should be supplementing with vitamin D. 

Nature also gives us other powerful nutrients and plants to help support us through the winter months. Traditional herbs like black elderberry and olive leaf are particularly helpful especially if combined with beta glucans which are found in oats and wholegrains. Mushrooms including reishi, maitake and shitake mushrooms also contain good amounts of these beta glucans.

It is often easier and more convenient to take a combination of nutrients that have immune support benefits. A good combination I use in my clinic is NHP’s Immune Support which contains botanicals - black elderberry, olive leaf; mushrooms - reishi, shitake and maitake; probiotics; beta 1, 3 glucans and the nutrients zinc, vitamin D and vitamin C. (NHP’s Immune Support).

Dr Marilyn Glenville PhD

Thank you so much for your time, for being our guest author and writing this informative article for our Walk the Walkers!

Dr Glenville runs clinics in Harley Street, London, Kent, Sussex and Ireland and also by phone, Zoom and Skype. For more information see www.glenvillenutrition.com or phone 01892 515905.



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