Are you puzzled when you look at the labels on your vitamins, or medicine for that matter and wonder why some say “Take with food”, others say “Take on empty stomach” and still others say “Don’t drink alcohol with this medication”? The answer has everything to do with solubility, or the ability of the body to absorb the material in the pill. For our purposes (vitamins and supplements), there are two groups of substances, water-soluble and fat-soluble.
Water-soluble vitamins, which include all of the B and C vitamins, are easily absorbed into the body. If you consume more of a water-soluble vitamin than you need, the excess will be excreted, not stored. This means the risk of an overdose is low, but you have to constantly replenish your stock. This is why it is possible to get Vitamin B12 shots from basically anywhere, because the worst that happens if you don’t need all of the nutrients is your urine turns a fun color for the rest of the day.
Fat-soluble vitamins, such as vitamins A and D, on the other hand require bile acids to help absorb them. These are longer lasting, and don’t end up being absorbed until your small intestines. They are stored primarily in your liver and other fatty tissues, and in some cases stay in the body for weeks or longer. There is a significantly higher risk of overdose with these vitamins in excess because a toxic level can build up over time without you realizing it. Don’t worry, a well-balanced diet will not lead to toxicity, but excessive vitamin supplementation might.
Why is this the case? Why do some vitamins just pass through the body and others linger? Well the short answer is because that is how your body evolved to cope during the hundreds of thousands of years when humans just barely had enough nutrients to survive. The B and C vitamins feed our energy and circulatory systems. They give you a boost of speed, or help protect your heart (no vitamin C did not prevent prehistoric colds, and it won’t prevent yours). These nutrients are fairly plentiful out in the big wild world, and so our bodies are used to not needing to store them. On the other hand, vitamins A and D are related to long term needs such as your vision and bones. They are harder to find in the wild, and as such our bodies have become very efficient at extracting these nutrients wherever they can be found, and storing them for as long as possible.
I know I know, you are waiting for me to address the last question….”Don’t drink alcohol with this medication”…the short answer is: that is nonsense. Of course you can drink while taking that medication. In fact you can literally drink while taking any medication. The problem comes the next day(s) when your body is trying to recover, because the warning that you ignored (and let’s be honest we all have at some point), was just a simple way of telling you that the medicine you are taking is hard on your liver…so give your liver a break.
That will be the topic for my next post — “The role of your liver in regulating inflammation, and why you get such f’ing bad hangovers”.