Everything you need to know about Vitamin C - from a Nutritionist

Vitamin C. The water-soluble vitamin that’s known for supporting our immune system, collagen production and packing an antioxidant punch. But with so many vitamin C products on the shelves - from tablets to powders, effervescent and liposomal - what do you need to know about this nutrient so you can consider how best to take it for your needs?

Natalie Louise Burrows, registered Nutritionist and Clinic Director of Integral Wellness , answered some of the most popular questions on vitamin C in this guide

Also known as ascorbic acid, Vitamin C is an essential water-soluble vitamin that plays a crucial role in numerous bodily functions. Unlike most animals (except primates and guinea pigs), humans cannot synthesise vitamin C, making it a necessary nutrient in our diet. As it’s water-soluble, it is either used or removed through urine (fat-soluble vitamins can be stored by the body and used in the future), so daily consumption is needed.

Vitamin C is involved in several vital processes within the body:

• Collagen: It's required to produce collagen, a protein essential for connective tissue (think skin) and maintaining the structure of blood vessels, bones, and skin.
• Antioxidant: As a powerful antioxidant, vitamin C helps protect cells against damage from free radicals.
• Immune system: Vitamin C is crucial for good immune function, helping the body fight infections and diseases.
• Iron absorption: It enhances the absorption of non-heme iron, the type found in plant-based foods.
• Brain health: Vitamin C creates certain neurotransmitters, chemical messengers essential for brain function and mood.
• Metabolism: It plays a role in the metabolism as vitamin C is a vital cofactor for many biochemical processes.

Vitamin C is best known for its role in preventing scurvy. In the Renaissance era (15th and 16th century), sailors were first found to suffer scurvy while onboard ships and away from fresh fruits and vegetables. Between the 16th and 18th centuries, over 2 million sailors lost their lives to this nutrient deficiency. The savour was fresh oranges, lemons, and limes brought onboard the ship for the sailors as part of their daily diet. This also earned the British sailors their nickname, Limeys.

Victorian-era scurvy and scabies are reported to be returning in the UK. Due to the cost of living, many people limit the fresh fruit and vegetables they buy and skip meals altogether. This is highly concerning for water-soluble nutrients like vitamin C (and B vitamins), which need to be consumed daily.

• Oranges, lemons, limes
• Red and green bell peppers
• Kiwi fruit
• Berries: strawberries, blackcurrants
• Broccoli
• Brussels sprouts
• Green peas
• Cauliflower
• Grapefruit
• Potatoes (especially baked)
• Cauliflower
• Spinach and other leafy greens
• Tomatoes
• Cantaloupe melon
• Mango
• Pineapple
• Papaya
• Acerola cherries
• Rose hips

Cooking can impact the amount of vitamin C in foods, as its water-solubility makes it easily lost during the cooking process. Because of this, raw fruits and vegetables contain the highest levels of vitamin C, but steaming is a great option for cooking as it tends only to lose 9-15% of the vitamin C content, which is much less than 50% from boiling. Sautéing and stir-frying are other good options when you keep the heat low.

The challenge with RDAs is that they are based on a healthy person and their assumed needs.

Vitamin C is a key antioxidant, and with the level of modern-day stress, pollution, and toxins, the body is in high demand for antioxidants (hence, smokers need more). Studies have shown that 1g of vitamin C a day can reduce the severity of a cold . Vitamin C deficiency would need to be treated with much higher doses, around 10g a day.

However, more isn’t always better. Although Vitamin C has a low toxicity risk, as it is a water-soluble nutrient excreted through urine if not used, high doses for long periods of time can impact iron absorption to the point that iron is at a toxic level, contributing to a condition called hemochromatosis, which impacts the liver. Understanding how nutrients interact with other elements in the body is key when supplementing.

Upper limits on nutrients exist for this reason:

Additionally, gastrointestinal problems can be a side effect of high-dose vitamin C, the most common being cramps, bloating, and loose stools (aka diarrhoea). Plus, taking too much will mean you’re paying for expensive urine.

The shelves are full of them, so here’s a quick guide to clarify the difference between all the vitamin C supplements on offer:

• Ascorbic acid is the form of vitamin C naturally found in food. Although it has great bioavailability, the acidity can be too impactful on some people’s gastrointestinal systems and cause side effects.
• Bioflavonoids is not vitamin C, but they are usually added to vitamin C supplements as they can increase the bioavailability of vitamin C and also offer beneficial compounds to support the immune system.
• Mineral ascorbates or buffered vitamin C is usually seen as magnesium ascorbate or calcium ascorbate. The term ‘buffered’ is because many people find this form much better for taking if they have a sensitive gut. This vitamin C is attached to a mineral compound (calcium, magnesium etc.), so you need to appreciate the dose of that nutrient when taking higher doses.
• Time-release vitamin C or esther-C is a slow-release option for this water-soluble vitamin. Because it is water-soluble, vitamin C should be taken in smaller doses throughout the day or in a slow-release form.
• Liposomal vitamin C is an encapsulated form of vitamin C in liposomes (tiny lipid spheres) that can potentially improve bioavailability. These often have a higher cost price as they are more expensive to create.
• Gummies are often used for children's supplements to make them more palatable. However, check for sugar content and include them after a meal if necessary, so they don’t act like a sweet.

Working with a registered nutritional therapist and personalised blood testing can ensure you take a supplement dose and form that’s right for your needs.

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