Vitamin C and Immune Health

Vitamin C

Vitamin C is necessary for our immune health. Below I discuss steps that you can take for yourself to maintain a healthy, balanced immune system. We don’t want an immune system that over-reacts and turns on your body or one that doesn’t react enough.

We place demands on our immune systems all the time and for the most part we are completely unaware of the tasks it is undertaking to protect us from pathogens such as bacteria, viruses and fungi. So in order for that to continue being the case, we need to provide our bodies with the best internal and external environments we can.

Supporting Immune Function

The immune system is highly complex. There are, however, some basic nutrients that have been shown to support its function.

Vitamin C is one of these. I will discuss what it is; why it is important; where we can source it from and how we can optimise the amount of vitamin C we can absorb. It is important to remember that we are what we absorb and not just what we eat.

The environment in the body needs to be functioning well to ensure that the nutrients we take in go to the cells, tissues and organs that need them. We also need to avoid foods like sugars that use up the nutrients in the body without providing any of their own.

What is vitamin C?

Vitamin C is also called ascorbic acid and is a water soluble vitamin. It cannot be made in the body and this is why we need to ensure that we get enough from the food that we eat. It also isn’t possible to store vitamin C in the body because it is water soluble and excreted easily in the urine. In order to maintain adequate amounts of the vitamin, it is better to spread your intake throughout the day and preferably include foods containing vitamin C in your daily diet.

Why is it needed?

The benefits of vitamin C to protect against bone, cartilage and tooth loss along with protecting against muscle wastage have been known for many years. It is also needed for collagen formation and wound healing; it helps us to absorb minerals such iron and calcium and it is essential for assisting with the functioning of the immune system. 

Vitamin C provides various roles in promoting immune function. Firstly, it protects the epithelial barriers in the body from the external environment (1). Epithelial barriers are found in the skin, the digestive tract as well as the nose, mouth, throat and the respiratory pathways including the lungs.

It also enhances the action of white blood cells in their defence against foreign invaders as well as removing dead cells from the body to reduce tissue damage (1).  

Powerful Antioxidant

Vitamin C acts as an antioxidant by donating electrons to unstable atoms or free radicals (1). Free radicals can be produced as a by-product of normal processes in the body such as breathing, liver and immune functions and exercise. They can alter the structure of proteins, fats and DNA in the body leading to disease (2). Viruses can also generate free radicals in the body. If these processes remain unchecked, the damage can grow and spread causing harmful inflammation.

If you think about how apples go brown when you cut them open and leave the flesh to come into contact with the air. You can slow down the browning process by squeezing lemon juice over the fruit. This works because the ascorbic acid (Vitamin C) in the lemon juice reacts with the oxygen in the air before the enzymes on the surface of the apple get a chance to react with it. The same goes for mopping up free radicals in the body by making sure you eat foods rich in antioxidants.

When we are looking for foods that are high in vitamin C, it is important to remember that we need to eat whole foods because we benefit from the addition of the other vitamins, minerals and fibre contained in these foods as all the components work synergistically together to give us the maximum health benefits.

So what can deplete vitamin C in the body?

A high level of sugar in the diet can lead to lower levels of vitamin C being allowed in to cells. This is because glucose and vitamin C share the same transporters to get into cells (3). If your diet is high in sugar, vitamin C will have to compete with glucose at the transporter sites.

Smoking also depletes vitamin C levels in the body (4).

How do we preserve vitamin C?  

The way we buy, store and prepare food can also affect the amounts of vitamin C we get from our food. So if we are not careful, Vitamin C can be depleted from our food before we can get a chance to eat it.

There are plenty of fruits and vegetables that contain vitamin C and ideally you want to include a good diversity of both in your diet. Heat damages vitamin C, so it is a good idea to consume fruit and raw vegetables when you can.

Cooking, storing and preparing Food

When you are cooking, use a steamer to lightly cook your vegetables. If you use as little heat and cook them for a shorter period of time you will preserve more vitamin C (5). Cutting fruit and vegetables depletes vitamin C, so only do this just before you want to eat them.

The same goes for storing them. The longer they are stored, the more of the vitamin is lost. Try to do a few shops when you are buying fresh produce. If this isn’t possible, then frozen fruit and vegetables are an excellent way of getting the maximum amount of nutrients from your food as they are often frozen directly after picking which preserves their freshness.   

Foods rich in vitamin C

Broccoli, Brussels sprouts, kale, peppers, chilli peppers, strawberries, lemons, oranges, kiwis, blackcurrants, parsley, thyme.


(1) Carr, A.C. & Maggini, S. (2017) Vitamin C and immune function. Nutrients, 9 (11).

(2) Lobo, V., Patil, A., Phatak, A. & Chandra, N. (2010) Free radicals, antioxidants and functional foods: Impact on human health. Pharmacognosy Reviews, 4 (8), pp.118–126.

(3) Santosh, H.N. & David, C.M. (2017) Role of ascorbic acid in diabetes mellitus: A comprehensive review. Pathology & Surgery, 4 (1), pp.1–3.

(4) Schectman, G., Byrd, J.C. & Gruchow, H.W. (1989) The influence of smoking on vitamin C status in adults. American Journal of Public Health, 79 (2), pp.158–162.

(5) Yuan, G.F., Sun, B., Yuan, J. & Wang, Q.M. (2009) Effects of different cooking methods on health-promoting compounds of broccoli. Journal of Zhejiang University: Science B, 10 (8), pp.580–588.

Please follow and like us:

Corporate Packages from £495

Corporate Nutrition and Lifestyle Course

This image has an empty alt attribute; its file name is Business-benefits-v5.jpg
Increased productivity; healthy and motivated employees; better communication are all areas that can be address by this Corporate Nutrition and Lifestyle course.

Benefits to your business

Investing in the health and welfare of your staff could help to improve your company performance. With increasing pressure on businesses it is important, now more than ever, to make sure that you look after the physical and mental wellbeing of your staff. This 4 week nutrition and lifestyle course aims to help you do that .

Benefits to your staff

The majority of employees are now being asked to work from home and may have to share their working environment with other family members. Their work load may have increased but they no longer have the immediate support of colleagues. This can lead to overwhelm and reduced productivity. Employees who work from home are also reporting loneliness and isolation.

Key aspects of the course

This is an online, interactive course run in an informal, relaxed manner. Participants are encouraged to actively participate by undertaking tasks during the week which are discussed in the following session. This enables the group to share their successes as well as gain further insight into aspects of their health.

It also gives participants the tools they need to make positive health and lifestyle changes for themselves after the course. Breakout rooms of smaller groups are used within the sessions to allow everyone to participate. This is a good way for colleagues to get together and can also connect people who would not normally be in contact at work.

Course content

7 Key areas:

1. What to eat and why.

2. Strategies to reduce stress.

3. The new “working norm”- optimising the home/ work environment.

4. Energy balance.

5. Why we need to exercise.

6. Digestive health to maintain immune function and reduce inflammation.

7. How to get a great night’s sleep.

A work booklet containing key aspects of the course will be provided.


 £495 up to 12 people

£795 up to 24 people (in 2 groups)

The courses can be altered to suit different business requirements. Tailor made programmes including aspects of health such as mid-life health, menopause and mental health can also be produced. Please contact me to discuss.

Here is what a recent client had to say:

“I thought it was really comprehensive. It was also very useful and well attended which is a testament to how relevant, informing and concise the sessions were. People were looking forward to learning more in the next session each time.”


MSV Housing, Trafford

To discuss a package to suit your business Contact me.

Please follow and like us:

Vitamin A

Vitamin A

What is vitamin A?

Vitamin A is an essential vitamin which means that we need to get if from our diet as it is not made in the body. It is a fat soluble vitamin and is available as preformed vitamin A from animal products and pro-vitamin A in fruits, vegetables and other plant based foods (1).

The levels of vitamin A in the body are dependent on levels of dietary intake; the capacity to absorb the micronutrient; the ability to convert the provitamin A to its bioavailable forms and how well it is taken up by the body’s tissues (2).

Retinol is the active form of vitamin A found in animal products and is easily accessible to the body. Due to its fat soluble properties, excess vitamin A is stored in the liver and adipose tissue (3). It is possible to consume too much vitamin A from animal sources and supplements.

Beta carotene is the most abundant carotenoid used by the body to synthesise vitamin A to its active forms retinol, retinal and retinoic acid. This is regulated by a homeostatic mechanism and is the safest way to consume vitamin A because toxic levels are not allowed to accumulate. Consuming large amounts can turn the skin orange but this is not harmful.

Western societies get more than 70% of their vitamin A from animal sources and less than 30% from plant sources. In contrast, populations in developing countries get more than 70% of their vitamin A intake from plants. 

Sources of vitamin A

Animal sources are liver, liver pate, milk, yogurt, oily fish (3).

Plant sources are pumpkins and squashes, sweet potato, carrots, parsley, green leafy vegetables including spinach and broccoli (3).

Health Benefits

Vitamin A is necessary to ensure the health of epithelial cells in the body. Epithelial cells cover all of the body’s surfaces. This includes maintenance of mucous membranes in the nasal passages, gastrointestinal tract, lungs, bladder, urinary tract and skin (5). Vitamin A is needed for growth and development in reproduction (5). Vitamin A is also necessary for maintaining bone, tooth health and eye health (5).

Immune health

A balanced immune response is also dependent on vitamin A which helps to promote and regulate the body’s innate and adaptive immune systems (5). This enhances the body’s ability to fight infectious diseases.

Recommended amounts

The recommended daily amount (RDA) of retinol is 700mcg for men and 600mcg for women in the 19-64 age range (4).


Supplements which contain more than 1500mcg of vitamin A from retinol should be avoided . High doses can cause birth defects in babies (4). For this reason, liver and liver products should be avoided during pregnancy as well as fish oils. If you are pregnant or trying for a baby do not exceed 1500mcg in total from food and supplements (4). If you are unsure what you should be taking, then consult your GP or nutrition professional. Some studies have shown an increased risk of bone damage and osteoporosis in menopausal women taking more than 1500mcg of vitamin A over several years (6). High dose supplementation is not recommended for smokers and non-smokers (7).


Vitamin A can interact with certain medications. See you GP or nutrition professional for more advice.

How do we increase our absorption of vitamin A?

Fat is needed to increase the absorption of vitamin A (3). Foods containing vitamin A should be eaten with healthy fats such as olive oil, extra virgin olive oil, avocado and nuts. Saturated fats such as coconut oil and butter in small quantities are also useful sources of healthy fats as part of a nutritious, balanced diet. Some diseases can result in poor absorption of fat. These include Crohn’s disease, Celiac disease, lactose intolerance and ulcerative colitis. As a result, they may deplete levels of fat soluble vitamins in the body.


(1). Albahrani, A.A. & Greaves, R.F. (2016) Fat-Soluble Vitamins: Clinical Indications and Current Challenges for Chromatographic Measurement. The Clinical biochemist. Reviews, 37 (1), pp.27–47. (2). Borel, P. & Desmarchelier, C. (2017) Genetic variations associated with vitamin a status and vitamin A bioavailability. Nutrients, 9. (3). Gilbert, C. (2013) What is vitamin A and why do we need it? Community Eye Health Journal, 26 (84), pp.65–65. (4). NHS.UK, 2020 Vitamin A [Online]. Available at: [Accessed 01/10/2020]. (5). Huang, Z., Liu, Y., Qi, G., Brand, D. & Zheng, S. (2018) Role of Vitamin A in the Immune System. Journal of Clinical Medicine, 7 (9), p.258. (6). SACN, 2005. Review of Dietary Advice on Vitamin A [Online}. Available at: [Accessed 01/10/2020]. (7). Satia, J.A., Littman, A., Slatore, C.G., Galanko, J.A. & White, E. (2009) Long-term use of β-carotene, retinol, lycopene, and lutein supplements and lung cancer risk: Results from the vitamins and lifestyle (vital) study. American Journal of Epidemiology, 169 (7), pp.815–828.

Please follow and like us: