Supplements make everyone feel better about their diet and nutrition, but here's four situations where supplements can do more harm than good. So before you take calcium, vitamin D3, iron, vitamin A or folic acid, read this:
1) Before you take Vitamin D...
While research has suggested that taking Vitamin D3 can have a positive impact on health if one is found to have low levels, the risks of too much vitamin D aren't commonly addressed. Vitamin D is now taken by the masses, often without proper testing to indicate a deficiency, and without proper monitoring.
According to Chris Kresser, "Furthermore, in most studies, taking vitamin D supplements does not decrease risk of death, cardiovascular disease, or other conditions. Based on an exhaustive review of over 1,000 studies in 2011, the Institute of Medicine recommends a much more conservative range of 20 to 50 ng/mL" 
From my own experience running hair analysis on people from all over the world, it's clear: excess vitamin D3 from supplements have a very negative impact on mineral levels, namely increasing calcium levels, lowering potassium levels, and lowering boron levels. This resulting mineral pattern can make one feel pretty sluggish. Symptoms such as brain fog, fatigue, slow-moving digestion, and blood sugar issues are common.
The main reason for this is your calcium to potassium level represents your thyroid ratio in hair analysis. The thyroid ratio affects how you actually feel.
So if you’re taking vitamin D3, which raises calcium levels and lowers potassium, you’re moving these minerals in the opposite direction of what supports thyroid health.
Don’t worry, once you know your levels with hair analysis, you can reverse this mineral pattern with targeted nutrition and supplementation.
2) Before you take Folic Acid...
You must know if you have a MTHFR deficiency.
Multivitamins often contain folic acid (the synthetic form of folate or vitamin B9) which can be harmful if you have a genetic mutation such as MTHFR. Methyl-tetra-hydro-folate reductase (MTHFR) is an enzyme that your body uses to convert folate (B9) into the active form of folate used by the body. This process is methylation.
Additionally, if you have a certain kind of MTHFR genetic mutation, even folate will not be enough, rendering the folate or folic acid as pretty useless for you. Here's some of the most common versions of the MTHFR genetic mutation, and how much it influences your body's ability to convert folate from food and supplements into methylfolate, the form that is useable by the body:
- MTHFR C677T = heterozygous mutation (one mutation) estimated up to 40% loss of function
- MTHFR T677T = homozygous mutation (two mutations) estimated up to 70% loss of function
- MTHFR A1298C = heterozygous mutation (one mutation) estimated up to 20% loss of function (limited research and controversy here)
- MTHFR C1298C = homozygous mutation (two mutations) estimated up to 40% loss of function
You can find out if you have one of the MTHFR genetic mutations by asking your doctor for the lab test or running your own by getting an ancestry test done and interpreting your raw genetic data with tools online. Note: They are constantly updating what these kinds of DNA tests show, so be sure to confirm that what you want out of it is still included before you order.
3) Before you take Calcium...
You must know your calcium level (I prefer hair analysis testing for this). Excess calcium is a real problem, and is more common than calcium deficiency (in my office at least).
Typically calcium levels won't get too high on their own from food alone (unless intake is excessive). It's when a calcium-rich diet is paired with calcium supplements and/or vitamin D3 supplements that calcium levels start creeping up. Soaring calcium levels can lead to calcification of your body. Think stiffness among other undesirable things, like back pain, joint issues, and osteoporosis.
A better bet for strong bones? Get some food-sourced calcium in your diet along with magnesium and boron (if you know you're low in these). And don't forget about the benefits of weight-bearing exercise for maintaining bone health.
4) Before you take Iron or Iron-containing supplements...
You must know your iron status. Too little iron and too much iron can both cause serious problems for your health, so supplementing blindly is never a good call.
If you're taking liver capsules or a multivitamin containing iron, make sure that you need it, and know that you're not at risk of iron overload (a situation where you absorb more iron from your food that normal). Find out more about your risk for iron overload here.
Iron testing used to be a normal part of blood work up until about 1997, so it's not out of line for you to ask your doctor for an iron panel that includes ferritin (iron stores). You can also order your own blood work here (about $48) if that is an easier option for you. However, you'll still need the help of your doctor to interpret the results.
5) Before You Take Vitamin A/Beta Carotene Containing Supplements...
Know that vitamin A deficiency is rare in developed countries and that vitamin A toxicity is a real thing. Vitamin A has been long touted as a nutritional superstar, although it’s found in almost all foods but most abundantly in a whole foods diet. By policy, it was added to low-fat milk products in 1970’s. It’s also found in multivitamins, supplements, skin creams (especially anti-aging creams), sunscreen, pharmaceutical drugs (like Accutane), and increases in the body if you’re on the birth control pill. It's also suspected that toxicity may occur at much lower dosage levels than reported in scientific literature.
If you suspect you’ve taken too much vitamin A from supplemental sources or what I call supplement stacking (ie. taking multiple supplements that make you double up on certain nutrients), there are a few things you can do right away. First, take a look at all your multivitamins, other supplements, lotions, prescription drug history, and beauty products to assess your intake. If there is excess, consider eliminating it.
So tell me, do you take any of these supplements? How do they make you feel? Please share in the comments!