Everyone knows Vitamin C is good for you. But most people couldn’t tell you exactly why — or whether they’re actually getting enough of it.
If your approach to Vitamin C is a glass of orange juice when you feel a cold coming on, this article is for you. Because this nutrient does far more than most people realise, and the question of how much you actually need each day is more nuanced than the standard guidance suggests.
What Vitamin C Actually Does in Your Body
Vitamin C — also known as ascorbic acid — is a water-soluble vitamin that your body cannot produce on its own. That makes getting it through diet or supplementation non-negotiable.
Your body uses Vitamin C across a remarkable range of functions. It drives the production of collagen, the structural protein that holds skin, joints, blood vessels, and tissues together. It acts as one of the body’s most powerful antioxidants, neutralising free radicals before they can damage cells. And it plays a central, multi-layered role in immune defence — which is what most people reach for it for.
How Vitamin C Supports Your Immune System
Your immune system relies on Vitamin C at almost every level of its operation.
At the first line of defence, Vitamin C strengthens the physical barriers — the skin and mucous membranes — that stop pathogens from entering your body in the first place. It also stimulates the production of white blood cells, including neutrophils and lymphocytes, which identify and destroy invading bacteria and viruses.
Once immune cells get to work, they generate free radicals as a by-product of fighting infection. Vitamin C protects those same immune cells from the oxidative damage they’d otherwise sustain in the process, helping them function more effectively for longer.
Research also shows that Vitamin C shortens the duration and reduces the severity of colds — even if it doesn’t prevent them outright in most people. For individuals under significant physical stress (athletes, people recovering from surgery, those dealing with chronic illness), the evidence for Vitamin C’s protective role is even stronger.
The Official Guidance — and Why It Falls Short
The UK recommended daily intake for Vitamin C sits at 40mg per day for adults. On paper, this sounds reasonable. In practice, it represents the minimum needed to prevent deficiency — not the amount needed to optimise immune function or antioxidant protection.
For context, a single 200ml glass of fresh orange juice contains roughly 80mg of Vitamin C. The fact that the official recommendation sits below what you’d get from one glass of juice tells you something important: the RDA was designed to prevent scurvy, not to support peak health.
Many nutrition researchers and clinicians argue that optimal intake — particularly for immune support — sits closer to 200mg to 1,000mg per day. The Linus Pauling Institute, one of the leading micronutrient research bodies in the world, recommends 400mg daily for healthy adults as a baseline for maximum tissue saturation.
How Much Is Too Much?
Because Vitamin C is water-soluble, your body excretes what it doesn’t use rather than storing it. This makes toxicity very unlikely at typical supplementation doses.
The UK’s safe upper limit sits at 1,000mg per day. At doses above this, some people experience digestive discomfort — primarily loose stools — as the gut reaches its absorption limit. This threshold varies between individuals, and many people tolerate doses above 1,000mg without any issues at all.
During periods of acute illness, stress, or intense physical exertion, your body burns through Vitamin C at a much faster rate. This is precisely when your need for it increases, and when supplementing above the standard daily dose becomes most justified.
Food Sources vs. Supplements — Do You Need Both?
Eating a diet rich in fresh fruit and vegetables will get you a solid base of Vitamin C. The best sources include:
- Red and yellow peppers (far higher in Vitamin C than oranges)
- Kiwi fruit
- Blackcurrants
- Broccoli and Brussels sprouts
- Citrus fruits
- Strawberries
The challenge is consistency. Vitamin C content in food degrades with heat, storage time, and cooking. Boiling broccoli can destroy up to 50% of its Vitamin C content. This makes it genuinely difficult to hit an optimal daily intake through food alone, day in and day out.
A high-quality supplement fills that gap reliably — giving your immune system a consistent, measurable supply regardless of what’s on your plate that day.
The Bottom Line
The 40mg official guideline keeps you out of deficiency. It doesn’t deliver the immune support, antioxidant protection, or cellular health benefits that Vitamin C is genuinely capable of providing.
Aim for 200mg to 1,000mg daily from a combination of food and supplementation. Increase your intake during winter, periods of high stress, or when you feel your immune system starting to struggle. And choose a supplement you can trust to deliver what it says on the label.
Body by Nature Supplements‘ Vitamin C gives you exactly that — clean, effective, properly dosed nutritional support for the immune system that works hardest to protect you.
Always consult your GP or a qualified healthcare professional before starting a new supplement routine.