Vitamin C and cold prevention.

Besides Tylenol and Ibuprofen, vitamic C is probably the most common suppement taken by those afflicted with the cold or upper respitory infections. I always have patients that prowdly let me know that they will fight off the cold or flu this season because they are loaded on vitamin C. So, lets take a look at this old warrior and see what he/she is up to.

What is Vitamin C:

Vitamin C is ascorbic acid. A water solube vitamin found in most fruits and vegetables. Vitamin C has few essential body functions:

• It helps with cell wall synthesis.

• It helps with collegen synthesis in bones, tendons, skin and hair.

• It is essential in immune cell differentiation, mobility and function.

• It is an anti-oxidant which helps with reducing inflammation.

So, vitamin C is essential for proper immune function. But vitamin C is also considered a micronutrient, meaning we need a very small amount of it on a daily basis. Since vitamin C is water solube our body is unable to store it in any large amounts. Dietary vitamin C is absorbed in the small intestine, enters the blood stream and is used by various organs. What is not used remains in the blood stream and is eventually filtered out by the kidneys and flushed down the toilet. Our brain, liver and muscles do store a small amount of Vitamin C, but without daily intake this reserve is depleted within a week.

Fun Fact: we only can store fat solube vitamins in large amounts: ADEK: vitamins A, D, E and K. These vitamins are stored in our liver and fat cells for future use. All other vitamins are water solube, we can not store any meaningful amount, so we depend on daily intake. Vitamin B12 is the only exception: it can be stored in the liver for years.

So, how much vitamin C do we need? And does it matter if we are fighting a mild infection like a viral upper respitory infetcion like Flu, COVID, RSV or any common cold?

It turns out that for most people the daily vitamic C requirement depends on age and sex.

AGE	MEN	WOMEN	PREGNANY	BREAST FEEDING
19+	90mg	75mg	85mg	120mg

Special populations:

1. Atheletes: if you are a super athelete, then you may need extra vitamin C per day, additional 30-50mg, as exercising causes inflammation and reactive oxygen species. Vitamin C is an important anti-oxidant.

2. Smoking causes oxidative stress in the body, so if you smoke you need an additional 35mg per day.

And now, the most important question:

What about illness? Does extra vitamin C help prevent infection? And what if you already have the sniffles, does extra vtamin C help shorten the duration of your illness?

Big drums: brum brum brum:

Not really, or at least not in any meaningful way. Sorry to burst your bubble.

The original idea of Vitamin C supplement to prevent or fight infection came from Linus Pauling's theories published in the 1970s. Although Linus was a genious and won two noble prizes, and correctly identified vitamin C and its role in immune system, but the findings were signfiicantly exagerated. These were based on poor research and mostly Linus's own recomendation: the idea that the more the better. Naturally the vitamin industry immediately picked up on this and vitamic C supplements have been a multi million dollar business ever since.

But there has been numerous randomized control studies since then that have refuted this theory. Yes vitamin C is essential for the immune system, and yes vitamic C helps ward off infection. But as long as you take adequate daily vitamin C through your diet, excess vitamin C does NOT boost your immune system, lowers risk of getting a viral illness or improve outcome.

Your immune cells are saturated with vitamin C with adequate diatary intake, any excess remains in the blood stream and is fitered by the kidneys. In other words, your immune system physically can not use more vitamin C than it needs.

There is also some evidence that excess vitamin C (above 500-1000mg) per serving can in fact slow the absorption as it overwhelms the small intestine's capacity to handle the large load. So, supplements with large quantities of vitamin C not only do not help, but may actually lower your body's ability to absorb vitamin C.

This is like a race car: A fancy expensive car like Ferrari competing for the Formula 1 podium needs high quality oil, but its engine only has space for a limited amount of oil, pouring more oil is simply going to spill over the ground. Not too much of a good thing is always good.

Foods high in Vitamin C:

For a robust immune system, you need to maintain a daily dose of vitamin C. Some fruits and vegetables are rich in Vitamin C and are the best surce of natural vitamin C. 3-4 servings per day is more than adequate.

Food source:	Vitamin C per serving:
Citrus fruits like orange	51mg
Mango	63
Kiwi	64
Strawberries	59
Bell pepper	95
broccoli	81 (per cup)
Medium Tomatoe	18

Some common fruits with less vitamin C include Apples (8mg), banana (10mg) and grapes (4mg per cup). As long as you eat 3-4 servings off various fruits and vegetables per day you will exceed your dialy vitamin C intake. Have I already mentioned that any excess vitamin C is simply filtered by the kidneys and flushed down the toilet.

Fun Fact: boiling reduces the vitamin C content, so if you plan to cook your fruits or vegebatles, try steaming or baking.

So, this fall and winter season save your money on vitamin C supplements. Instead make sure you eat plenty of fresh fruits and vegetables, get a good night sleep (sleep is also essential for a healthy immune system), exercise and hydrate. And instead of spending your money on vitamin C, buy few lottery tickets, win, and throw a Emerald Party at the next Cavs game. Of course with plenty of fruits and vegetables to serve.