Food-Based Vitamins vs. Synthetic Vitamins: Which Is Better?

You may wonder if you get enough vitamins from the food you eat or if you need to take a vitamin supplement to be healthy. There are some important differences between food-based vitamins and synthetic vitamins. 

In general, experts recommend food-based vitamins as the better choice. But what if you aren’t getting enough? We’ll discuss the important aspects of each option, and when it makes sense to take synthetic vitamins.

What’s the difference between synthetic and food-based (natural) vitamins?

Synthetic vitamins are made by chemical processes in laboratories. Vitamins in supplements and multivitamins are often synthetic. But not always. Some vitamin supplements — found in bottles — are derived from food and contain natural vitamins. And the opposite is true, too. Some foods — like cereals and breads — may have synthetic vitamins added to them.

In contrast, food-based vitamins refer to vitamins that are naturally found in foods. Here’s a list of some important vitamins and examples of foods where you can find them:

• Vitamin A: eggs, dairy, fish, organ meats, and fruits and vegetables

• Vitamin B1 (thiamine): whole grains, meat, and fish

• Vitamin B3 (niacin): animal products, nuts, seeds and grains

• Vitamin B9 (folate): spinach, liver, asparagus, and Brussels sprouts

• Vitamin B12: animal-based foods

• Vitamin C: citrus fruit, tomatoes, peppers, and potatoes

• Vitamin D: fatty fish, other animal products, and mushrooms

• Vitamin E: nuts, seeds, cooking oils, and green leafy vegetables

Are food-based vitamins better for you?

The Dietary Guidelines for Americans recommends meeting nutritional needs with food, if possible. You should get enough vitamins if you eat a diet with a variety of foods. 

Food-based vitamins also come with fiber, fats, enzymes, and other vitamins. These other components help your body use these vitamins more efficiently. 

But some people may still need to take synthetic vitamins to get the recommended amount. These include people who:

• Have certain conditions (more on this below) 

• Have had gastrointestinal surgery (which can affect the gut’s ability to absorb food-based vitamins) 

• Take certain medications (more on this below)

• Need folic acid (because they’re or may become pregnant)

• Don’t eat animal products (the primary source of vitamin B12)

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In these situations, synthetic vitamins are helpful and sometimes necessary. But synthetic vitamins often come in much higher doses than what naturally occurs in food. So overdoses of vitamins are more likely to happen when taking synthetic vitamins. For example, vitamin B3 (niacin) and vitamin E overdoses have been seen with supplements, but not food. 

Can synthetic vitamins be harmful?

Yes, synthetic vitamins can be harmful. This is especially true in high doses and for fat-soluble vitamins. 

To understand why fat-soluble vitamins can be problematic, it helps to understand how the body processes (or absorbs) another type of vitamin. 

Water-soluble vitamins get dissolved and transported throughout your body by water. And if you have too much of a water-soluble vitamin, your body easily gets rid of it through your urine. This protects you from having too much in your body at any one time. 

Water-soluble vitamins include:

• Vitamin B1 (thiamine)

• Vitamin B9 (folate)

• Vitamin B12

• Vitamin C 

Fat-soluble vitamins are the other, riskier type of vitamin. That’s because the body can’t remove excess amounts through your urine. Instead, fat-soluble vitamins build up in the liver and fatty tissue in the body. 

Here are some fat-soluble vitamins and their health risks in high doses:

• Vitamin A: This can lead to headache, vision problems, nausea, dizziness, and muscle aches. During pregnancy, excess vitamin A can cause birth defects.

• Beta-carotene (provitamin A): This has been linked to increased lung cancer in people who smoked.

• Vitamin D: This can lead to gastrointestinal, musculoskeletal, cardiovascular, renal, and nervous system problems. This is most often caused by people taking too many supplements.

• Vitamin E: This has been linked to increased risk of hemorrhagic stroke. There’s a possible increased risk of prostate cancer.

Another potential risk associated with synthetic vitamins is that they’re often not regulated by the FDA. Less regulation can mean incorrect labels, so you don’t always know what (or how much) you’re getting.

But there is one water-soluble vitamin that can be risky in high doses. Vitamin B3 (niacin) is a treatment for cholesterol disorders. In high amounts, it can cause skin flushing, liver damage, and high blood sugar.

Which diseases and medications decrease vitamin absorption?

The body is usually very efficient at absorbing vitamins from food and supplements. But some conditions and medications can make it harder for the body to absorb (and get the benefits of) certain vitamins. 

Gastrointestinal conditions make people much more likely to have vitamin deficiencies. That’s because most vitamin absorption happens in the small intestine. So conditions that affect the gut can make it harder to absorb vitamins. Some examples of these conditions include:

• Inflammatory bowel disease (ulcerative colitis and Crohn’s disease)

• Cholestasis

• Pancreatic disease

• Cystic fibrosis

• Intestinal resection

• Bariatric surgery

But lots of other things can make it hard for the body to absorb vitamins, which can lead to a lack of certain ones. 

Here’s a list of specific vitamin deficiencies and their possible causes, including medications that can lead to low levels.

Potential causes of vitamin B1 (thiamine) deficiency include: 

• Alcohol use disorder

• HIV

• Diabetes

• Dialysis

• Hyperemesis gravidarum

• Medications, including furosemide and fluorouracil

Potential causes of vitamin B9 (folate) deficiency include: 

• A limited diet that does not contain leafy greens, animal products, beans, or foods fortified with B9 

• Alcohol use disorder

• Medications, including phenytoin, carbamazepine, valproic acid, and sulfasalazine

Potential causes of vitamin B12 deficiency include: 

• Vegetarian or vegan diet

• Pernicious anemia

• Autoimmune diseases, like Graves’ disease, hypothyroidism, and Addison’s disease

• HIV

• Medications, including metformin, omeprazole, ranitidine, and oral contraceptives

Potential causes of vitamin C deficiency include: 

• A limited diet that does not contain fruits, vegetables, or a variety of foods 

• Smoking

• Dialysis

Potential causes of vitamin D deficiency include: 

• Limited sunshine exposure to the skin 

• Medications, including phenytoin, carbamazepine, isoniazid, rifampicin, cholestyramine, and ketoconazole

Potential causes of vitamin E deficiency include: 

• Low-fat diets 

• Some rare metabolic disorders

How can you increase vitamin absorption?

If you don’t have any of the above conditions, your body can probably absorb vitamins just fine. But if you’re working with a healthcare professional (like a dietitian or nutritionist) to get more of a certain vitamin, it may help to know more about vitamin absorption.

There are some differences in how vitamins are absorbed or made available for the body’s tissues. Here are some of those differences and examples:

• Chemical formula of the vitamin: Sometimes certain forms of the same vitamin are better absorbed. This has to do with differences in the shape of the molecule. For example, the RRR-ɑ-tocopherol (or d-ɑ-tocopherol) version of vitamin E is better absorbed than the all-rac-ɑ-tocopherol (or dl-ɑ-tocopherol) version. 

• Water solubility: People with poor fat absorption will likely also have poor absorption of fat-soluble vitamins. Poor fat absorption occurs with Crohn’s disease, cystic fibrosis, and certain gallbladder problems. Taking a water-soluble version can increase vitamin E absorption. 

• Vitamin form (route): Vitamins can come in different routes to the body, which can affect absorption. Vitamin B12 is available in oral, sublingual, nasal spray, and injection forms. Injections have the best absorption and are especially important for people who have conditions like pernicious anemia. 

• Vitamins with food: Taking a vitamin with food can change the absorption. For example, folate is more available when you take it without food. And vitamin D is better absorbed when you eat food with fat.

• Food preparation: The way foods are prepared can affect food-based vitamin content and absorption. In general, the less processed the food, the more vitamins remain. For example, heating foods can reduce thiamine. And vitamin C is higher in raw, fresh foods.

• Food sources: Absorption can vary between different food sources for the same vitamin. Vitamin B12 is absorbed better from dairy products than from meat or fish.

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Written by:

Katherine Krive, DO

Katherine Krive, DO, is a freelance medical writer and editor. She is also a psychiatrist who has practiced in hospital, academic, and community settings.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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