How Do Vitamins Work? The Science Behind Their Absorption
Many of the foods we eat naturally contain vitamins and other nutrients, while others are fortified, such as milk with added vitamin D. Still, some people lack certain essential vitamins due to their diet, age, gender, genetics or other factors. To compensate, many take supplements, such as multivitamins, that deliver a variety of vitamins and minerals in every dose.
How do vitamins work in the body? Let’s explore this topic and examine the ongoing controversy surrounding supplement efficacy within medical and scientific communities.
How Do Vitamin Supplements Travel Through Your Body?
Here’s a step-by-step explanation of how vitamins travel through the human body:
- You swallow the vitamin supplement, and it moves down the esophagus to the stomach.
- In the stomach, digestion begins. Digestive acids and enzymes begin to dissolve the supplement, but it’s not fully digested here.
- The remaining portion travels to the small intestine, where it’s further broken down by digestive enzymes and fluids from the liver and pancreas.
- In the second and third parts of the small intestine, nutrients from the digested supplement are absorbed into the intestinal lining. From here, the method of entry into the bloodstream depends on the type of vitamin:
- Water-soluble vitamins (B and C) are absorbed directly into the bloodstream.
- Fat-soluble vitamins (A, D, E and K) must be broken down by bile acids before being absorbed. These are then absorbed by the lymphatic system and transported into the bloodstream.
- The bloodstream carries the beneficial portions of the vitamin to various cells and tissues in the body.
- Excess water-soluble vitamins and their byproducts exit the body through urine, while remaining fat-soluble vitamins are stored in the liver and fatty tissues for later use.
What Is the Role of Vitamins in Our Bodies?
Vitamins play crucial roles throughout the body, aiding each organ, tissue and cell in different ways. They help:
- Fight infections
- Improve vision
- Build strong bones and muscles
- Regulate hormones
Many cells in our bodies, from skin to bone, regenerate regularly to replace old and damaged ones. For example, the outer layer of our skin cells renews about once a month. This regeneration process requires vitamins, whether obtained from food or supplements, making them essential to the normal, healthy functioning of the body.
What’s the Controversy Behind Vitamin Supplements?
While taking vitamin supplements may seem beneficial, many experts argue that vitamins in supplement form provide little to no health value compared to those obtained through food. Some point to scant evidence that supplements prevent or cure any major diseases.
Others contend that the body does absorb beneficial vitamins from supplements but eliminates excess amounts through urination — a potentially favorable scenario. Most experts agree that the best way to obtain vitamins is through a nutrient-rich diet rather than supplements.
Go Deeper Into the Science of the Human Body
If this made you think more seriously about a future in medicine, pharmacy, research or healthcare, UF’s online medical sciences programs can help you build that foundation.
Sources:
https://ods.od.nih.gov/factsheets/WYNTK-Consumer/
https://www.hopkinsmedicine.org/health/wellness-and-prevention/is-there-really-any-benefit-to-multivitamins
https://www.prevention.com/life/a20474960/how-to-make-sure-youre-benefiting-from-your-vitamins/
https://health.clevelandclinic.org/which-vitamins-should-you-take
https://my.clevelandclinic.org/health/body/7041-digestive-system
https://time.com/6171584/are-vitamins-supplements-healthy/
