Vitamin Absorption: What Really Happens in Your Body?

If you’re taking a Vitamin, you might assume your body is soaking up all those nutrients like a sponge. But the truth is, how much your body actually absorbs can vary widely based on several factors.

Let’s dive into how vitamin absorption works, and what science says about making the most of your daily dose.

What Does “Absorption” Mean, Anyway?

When we talk about vitamin “absorption,” we’re referring to the process by which nutrients move from your digestive tract into your bloodstream. From there, they can be transported to cells and tissues where they’re needed.

But not all of a vitamin supplement actually gets absorbed. Some nutrients are lost in digestion, poorly absorbed due to chemical form, or excreted because the body can’t use them immediately.

Forms Matter: Bioavailability of Vitamins

The term bioavailability describes how easily a nutrient can be absorbed and used by the body. Certain forms of vitamins and minerals are simply more bioavailable than others.

For example:

• Folic acid (a synthetic form of folate) must be converted by the liver before becoming active. In contrast, L-methylfolate, the active form, is absorbed and used more efficiently, especially in people with MTHFR gene variations [1].
• Chelated minerals, where the mineral is bound to an amino acid, are often better tolerated and absorbed. Magnesium Glycinate is a great example of this.

Study Spotlight: A 2003 review in The American Journal of Clinical Nutrition found that the chemical form of a nutrient significantly affects its bioavailability, particularly for minerals like iron, calcium, and zinc [2].

Fat-Soluble vs. Water-Soluble Vitamins

Vitamins are classified as either:

• Fat-soluble (A, D, E, K): These need dietary fat to be absorbed properly.
• Water-soluble (B-complex and C): These dissolve in water and are absorbed quickly, but excess amounts are usually excreted in urine.

If you’re taking a vitamin that is fat-soluble on an empty stomach or with a low-fat meal, your absorption could be significantly reduced. This is likely where the myth of "Vitamins and supplements aren't absorbed into your body as well as regular food" stems from.

Study Spotlight: A 2015 study in the Journal of the Academy of Nutrition and Dietetics showed that co-ingesting vitamin D with fat increases absorption by up to 32% compared to taking it on an empty stomach [3].

Digestive Health and Absorption

Your gut plays a critical role in vitamin absorption. Conditions like celiac disease, Crohn’s disease, or low stomach acid can impair your body’s ability to absorb certain nutrients.

Older adults may also experience reduced absorption due to atrophic gastritis, which lowers stomach acid and impacts the uptake of vitamin B12, calcium, and iron [4].

Gut health can be improved most easily by eating a balanced diet with plenty of fiber.

Tips to Improve Vitamin Absorption

Here’s how to ensure you’re getting the most from your vitamins:

Take with food – Especially a meal that contains healthy fats.

Avoid high-calcium foods with iron supplements – Calcium can inhibit iron absorption.

Stay consistent – Nutrient levels build up over time.

Check the label – Look for active or chelated forms of nutrients.

Talk to your doctor – If you have absorption issues, you may need higher doses or different forms.

Final Thoughts

Vitamins can be a powerful support for your health, but absorption is key. Choosing a high-quality product with bioavailable forms like Zivra, taking it with food, and supporting your gut health can all improve how well your body uses the nutrients.

Because at the end of the day, it’s not just what you take—it’s what your body actually absorbs.

References

1. Scaglione, F., & Panzavolta, G. (2014). Folate, folic acid and 5-methyltetrahydrofolate are not the same thing. Current Drug Metabolism, 15(1), 61–73. https://doi.org/10.2174/1389200214666131210220519
2. Fairweather-Tait, S. J., et al. (2003). Bioavailability of minerals and trace elements. The American Journal of Clinical Nutrition, 79(5), 921–932. https://doi.org/10.1093/ajcn/79.5.921
3. Mulligan, G. B., & Licata, A. (2015). Taking vitamin D with the largest meal improves absorption. Journal of the Academy of Nutrition and Dietetics, 110(4), 545–549. https://doi.org/10.1016/j.jada.2010.01.009
4. Allen, L. H. (2009). How common is vitamin B-12 deficiency? The American Journal of Clinical Nutrition, 89(2), 693S–696S. https://doi.org/10.3945/ajcn.2008.26947A