Does Vitamin C help prevent flu?

Vitamins, supplements, preventions and treatments

So much to address! So broad a topic that gets often addressed to us at the counter and at home, and that so often leaves us indecisive and ignorant or overconfident…

Let’s start with one of the questions you hear most in winter: “Do you think I should take vitamin C to prevent these colds out there?”

Now, (as always) let’s begin the explanation lesson. Please sit down and look at the picture so we can begin to complicate our response, because if the answer were easy, there would not even be a need for a question.

1 – What is a vitamin, and what is Vitamin C in particular? This question may seem obvious, but there are many misunderstandings about vitamins that have to be clarified.

2 – What is a cold?

3 – Is Vitamin C adequate to prevent flu and colds? And to cure them?

  1. A vitamin is a micronutrient that the body needs to survive. Do you see that word in italic there? It’s important. Some time ago we reminded people how it “the dosage that makes the poison”. Well, the same principle applies to vitamins: they are essential, but only in their proper amounts. Usually, we can get the vitamins we need, in the right amounts, through a varied and balanced diet (yes, I know that this expression is so used that it already goes over us, but it is because it is very important!).

1.1. Vitamins are very different from each other, and have only the name in common. They act on very different metabolic pathways, are soluble in different solvents, are necessary or toxic in very different amounts… To get an idea, the recommended daily dose of vitamin C is 45,000 times higher than the dose of vitamin B12. And since I’ve already got the conversation going, here goes…

1.1.1. Vitamin C (ascorbic acid) has two great “advantages” over some of the other vitamins: it is cheap and the dosage needs to be very high to become toxic. Thus, although we only need about 90mg per day, we can take up to 2000mg per day without expecting adverse effects. In fact, there are stories of crazy people like Linus Pauling who claimed to take 4g a day, every day (up to 12g in some heights), and apparently would not suffer major side effects.

1.1.2. But is this why we also start taking the so-called “horse dosage” of vitamin C? No. Go on, think with me: our body simply does not need that whole amount. In fact, it doesn’t even know what to do! It cannot be in the blood because it changes its acidity, or osmolarity, or so … It can be absorbed into some cells, but it comes to a point when the cells themselves are full! So, do what you have always done with excesses, and get rid of it.

Thus, we “discover” one of the most common effects of excessive dosage of vitamin C, diarrhea and some kidney problems, because sometimes it stays in the digestive tract and is not absorbed, sometimes it is absorbed and, due to excess, is soon excreted by the kidneys. Sometimes this can be helpful, and renal excretion of vitamin C is used as a way to acidify urine (which may give way to some diseases).

2. A cold is a viral disease. I repeat: VIRAL (and not bacterial, so it’s not even worth taking antibiotics). We all know the symptoms, I’m not going to go over them here. But the important part is that it is a disease that our body under normal conditions can fight alone (as long as we are not compromising the immune system). Medications for colds help us feel better while the body treats the subject.

3. Vitamin C is used to prevent flu and colds in 2 groups of people:

– People who do not ingest the daily dose of vitamin C (and are therefore half way to getting scurvy;

– Athletes who subject the body to high physical effort.

In these two groups, vitamin C supplementation may actually help prevent a cold.

3.0.1. The dosage may vary, some sources suggest that it is no use to exceed 250mg daily… But we can be more aggressive and, in the absence of risks and side effects, recommend 1g per day without risking anything in particular.

3.1. For the treatment of colds, there is some evidence that supplementing with vitamin C (in the same dosage as before) may actually help reduce the severity of symptoms and their duration, even though the results are marginal, at best.

Let me just wrap up with two points so that they are clear:

– The fact that we can take vitamin C without great danger of overdose cannot be extrapolated to other vitamins.

– Although we can usually cope with excess vitamin C, this is no reason to be testing our “normal” with “abnormal” takings. After all: * vitamins are nutrients that can be obtained in their right quantities through a balanced diet! *

And there you have, I’m finishing today’s class. If you have questions or concerns, you already know that you can ask your pharmacist.


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