Why Your Fitness App Can’t Tell If You Have a Vitamin Deficiency
Diet tracking tools often include data on the vitamins and minerals you are getting (or not getting). While it’s okay to motivate yourself to eat a few extra vegetables, you shouldn’t immediately jump to the conclusion that you are vitamin deficient or need mega-dose supplements. That’s why.
Why diet trackers are wrong
You’ve probably noticed that we don’t always remember well when we track. (It’s not just you; a lot of scientific research has been criticized because it is based on asking people what they ate, and people are often wrong.) It is often helpful to enter foods, measure accurate amounts, and improve your estimation skills , but numbers in your diet tracking program will never be the absolute truth .
You also don’t have complete control over the information. Many foods do not provide complete information on vitamins and minerals in the databases, and only a few micronutrients are required on food labels: vitamins A and C, as well as the minerals sodium, iron and calcium. Therefore, even if you enter data directly from labels, you may be missing important components. This means that your daily vitamin intake – especially if it is not usually listed – may be lower than it actually is, simply because some data is missing.
Another thing we often forget: our diets change with the seasons and over time. (How many pumpkin spiced lattes did you eat in April? How much ice cream in January? How many hearty beef stews in the middle of summer?) Tracking what you eat for days or weeks, even if you might somehow be doing it ideally, does not really reflect your overall diet.
Then why track vitamins at all? In all fairness, most people probably don’t. If you already know (from previous conversations with a dietitian or other health professional) that you have a health problem and need to monitor your intake of a particular nutrient, tracking gives you the ability to track (approximate) data about that. But if you’re trying to pinpoint a problem or deficiency in the first place, a food log alone isn’t enough.
How Many Nutrients Are “Too Much”?
Everyone has their own personal needs for each nutrient. For example, a large person may need more than a small person, women may need more than men (or vice versa), and many requirements change with age. Diet tracking software can account for these factors, but there are also person-to-person differences that the software cannot track: you may genetically need a little more or less than I do.
The people who calculate the recommendations understand this, so they are not claiming that the recommended amount of the vitamin is ideal for everyone. They study the distribution of nutrient needs in a population and set a RR (the amount you “should” get) that will meet or exceed the needs of 97% of people. This means that 97% of people need this amount or less . If you are getting less RDI, but you feel good, in fact, you may be fine.
What if you think you are getting too much of something? While some nutrients have highly publicized upper limits (like the sodium recommendation you should stick to), for most vitamins and minerals the upper limit is somewhat unclear. Here is the table you will need to know if you are really getting too much.
This means you can get more than 100% of the recommended amount (RDI) of the nutrient, but you still don’t get too much. For example, there is no known upper limit for vitamin B12, so you can consume as much as you want. (If overdose is possible, science hasn’t noticed yet.) Others have fairly high upper limits: you can get 2000% of your recommended vitamin C intake every day and you should be fine. However, you will reach the upper limit for zinc – just 400% of the RDI. So if you are intimidated by a high percentage, don’t worry until you check if you are indeed exceeding the upper limit on a regular basis.
Diet is only one piece of the puzzle.
It’s easy to focus on data that’s right in front of us, like your diet tracker reports. But sometimes it obscures the rest of the picture, where we don’t have exact numbers.
A good health professional will not diagnose you with a deficiency based on the results of several weeks of diet tracking. They will link this data with other information about your health to figure out what’s really going on.
For example, they may order a test to find out how much iron or vitamin D is circulating in your bloodstream. They may ask about aspects of your life that could change your need for nutrients or your ability to get them from other sources. (For example, if you spend a lot of time in the sun , dietary vitamin D becomes much less important. And if you are African American, your vitamin D blood test results may be low, even if you are not deficient.)
And perhaps most importantly, they can investigate you. If you are worried about your diet because of symptoms that you believe are related to a deficiency, do not stay at home ordering vitamin pills; go to the doctor already, where they can check if your symptoms really indicate a deficiency, or if your problem could be any of the many other things that can go wrong with the human body.
Photos by Shannon Kringen , Martinak15 , Melissa .
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