Why fruits and vegetables are healthy? Because they are packed with vitamins, minerals and fiber!
Everybody knows that vitamins contribute to good health, supported immune system, beautiful skin, hair, and nails. You can supply your body with these micronutrients through diverse and balanced diet, or by supplementing with specific vitamins.
That being said, there are different types of vitamins. In foods, these are perfectly combined to provide you with optimal health benefits. However, due to various health conditions and lack of balanced diet, people could develop vitamin deficiencies.
Nowadays, prescribing vitamin supplementation (as part of more complex disease treatment) has become a popular practice among health professionals. This incentive has shown significant decrease in the number of vitamin deficient individuals globally.
However, a lot of people reach to supplements without consulting their doctor. This not only can pose severe heath risks, but can also lead to inappropriate supplement combinations.
This article will guide you through the different types of vitamins and will show you what vitamin supplements ARE and ARE NOT recommended to be taken together.
Let’s dive in!
What exactly are vitamins?
According to MedlinePlus, vitamins are a group of substances that are needed for normal cell function, growth, and development. 
In total, 13 vitamins exist, as each of them has different purpose and function in the body. Together, these micronutrients support healthy organ and system functions (immune, nervous, digestive, cardiac, etc.), physical as well as mental health. Any vitamin deficiencies can pose significant health risk and may trouble the proper body functions.
That being said, the body needs very little amounts of vitamins in order to support healthy cells, organs, and tissues. And getting enough vitamins through food can be easy as long as you stick to balanced and diverse diet (containing veggies, fruits, whole grains, and some animal-based products), and don’t suffer from any health conditions that trouble the absorption of these nutrients. 
Yet, vitamin deficiencies occur often. And in to recover the depleted levels of micronutrients, a prescribed supplementation is strongly needed.
What are fat and water soluble vitamins?
There are two vitamin categories: fat-soluble and water-soluble.
What are fat soluble vitamins?
Fat-soluble vitamins include vitamin A, D, E, and K. They are heat stable, so foods that contain fat-soluble vitamins continue to be as nutritious after being cooked (or heated). 
When consumed, they are absorbed in a similar way that fats are absorbed, and their excess amounts are stored in the liver and fatty tissues for a long time. In that sense, there are significant concerns that taking large doses of fat-soluble vitamins can be related to various risks, including increased chance of toxicity (as excess amounts are not excreted). 
That being said, sufficient amounts of fat-soluble vitamins are usually supplied through balanced diet, but additional uncontrolled supplementation may increase the risk of overdose.
Another important thing to mention is that some health conditions which limit the absorption of fat could also trouble the absorption of fat-soluble vitamins. Evidence suggests that such health issues include inflammatory bowel disease (IBD), chronic pancreatitis, and cystic fibrosis. As a result, patients suffering from these health conditions may be more predisposed to vitamins A, D, E, and K deficiencies.
What are water soluble vitamins?
Water-soluble vitamins include vitamin C, and B-group vitamins (thiamine- B1, riboflavin- B2, niacin- B3, pantothenic acid- B5, pyridoxine- B6, biotin- B7, fcobalamin- B12). These are not heat-stable, which means that cooking foods rich in vitamins B and C can decrease the availability of those vitamins. Besides, lack of proper storage of such foods can also decrease their vitamin abundance. For that reason, refrigerating and low-heat cooking can help you preserve large amounts of these micronutriens. 
Generally, excess amounts of water-soluble vitamins are excreted out of the body with urine. That being said, the consumption of B and C vitamins should be daily, preferably through balanced diet. However, evidence suggests that megadoses or continuous intake of high doses of these vitamins (this can happen due to uncontrolled supplementation) may lead to toxicity, dependency, withdrawal symptoms, or malabsorption of medicines. 
Why take vitamin supplements?
In foods, vitamins are well combined to ensure high degree of absorption. However, if you can’t manage to ensure sufficient vitamins intake, you may develop deficiency/insufficiency symptoms, which strongly depend on the type of vitamin deficiency you suffer from. Some common types include vitamin A, D, folate, and B12 (cobalamin) deficiencies. 
That being said, supplementation with a single vitamin or combination of vitamins is a common practice prescribed by health professionals to support their patients recover the depleted levels of vitamins in the body. When recommended and supervised by a doctor, supplementation can quickly improve the quality of life of deficient individuals and prevent more severe deficiency symptoms and related health conditions.
When prescribing supplements, doctors may take into account different factors that impact the supplementation process:
- Degree of deficiency (intensity of symptoms and blood test results)
- Other vitamins or minerals that support the absorption of the deficient vitamin
- Lifestyle factors that may trouble the absorption of the deficient vitamin
- Length of safe supplementation
In that sense, self-guided supplementation does not take into account the above mentioned factors, and can lead to increased risk of toxicity or the contrary- lack of health improvement.
Which vitamins work best together?
When taken together, some vitamin and mineral supplements are absorbed better than when taken separately.   Good combinations include:
- Vitamin B12 + Folate
- Vitamin D + Calcium
- Soluble vitamins + Dietary fat (e.g., olive oil, avocado, fish)
- Vitamin C + Iron
- Vitamin B12 + Acidic foods
Some vitamin combinations that are not recommended are:
- Pair or combination of two or more fat-soluble vitamins (e.g., Vitamins E+D)
- Vitamin C + Vitamin B12