i checked a lot of supplements and every time i see that the daily dose is much higher as the recommendation. so for example for vitamin b12 the recommendation for adults is 3 micrograms but the lowest supplement i found was 7 micrograms for one dose and the same for fat soluble vitamins - for example vitamin D. is there something about the absorption or why are the doses for any kind of supplements so high?
ps: im talking about supplements without prescription
Our ability to absorb some vitamins, like B12, is not 100%, so supplementing above the RDA helps ensure you’ll actually absorb the amount you need. This isn’t the case with all supplements though, some are just excessive. Look up the UL and be sure to not exceed it through the supplements and food you take/eat.
The amount on those supplements do not equate to the amount that you’re going to absorb and more importantly the amount that you as an individual need to be healthy and, even more than that, optimally healthy.
Your genetics, gender, ethnicity, body weight, health conditions, stress, and lifestyle are examples of factors that are going to influence the amount of a particular nutrient you’re going to need to be healthy. And so the only way to know the right amounts is to measure that in blood for certain key nutrients to see if you are storing and are maintaining a certain level.
So for example, with iron you’ll see the very low numbers it could be 6 mg for iron or it could be even less.. because it can be toxic. But upper limit for iron is 45 mg. Now if someone is has anemia they might be taking 35 mg, 65 mg, 170 mg per day for a period of time in order to get their levels up. And there are other nutrients and foods that can help support absorption and maintaining your iron levels as well. However, there’s going to be a certain amount you’re going to take to maintain a healthy blood level.
Another big nutrient we’re hearing in the news is vitamin D. For years this nutrient has been underplayed and talked about in its importance. The upper limit for vitamin D is 4000 IU or 100 µg. I was taught that you need 50 ng/mL in your blood in order to maintain bone health and in order for vitamin D to do anything else in terms of health for your body. Several different experts say we need between 40 to 80 ng/mL for immune health. Yet blood levels of 30 ng is adequate in labs, but it’s not if we’re looking at important factors when it comes to health.
For example, my doctor wanted me to be at 80 ng/mL of vitamin D. In order to maintain that I had to take 8000 IUs per day. And I have been good at it for several years but I slacked on that for several months and was taking half the dose because it was coming only from my high potency multivitamin & mineral and it dropped my level down to 60 ng/ml. Still considered within healthy range but I’ve begun supplementing separately as well.
And there are various resources, including of course your doctor, dietitian nutritionist, that can guide you on the amount to take based on a certain health condition. In the case of Vitamin D, the only way you’re going to know is to take the higher dose daily or weekly, usually your doctor prescribes for you, and once you hit the right level in your blood that your doctor wants that is the amount you’re typically going to keep taking to maintain it. Of course, you can get your levels check twice per year and make some adjustments, but it’s not something you take for a short period time and stop you’re always going to supplement and/or getting some of it through diet, but most of it’s likely going to come from supplementation (and working on enhancing absorption to need lower amounts) based on lab results and health goals.