The accepted view is that synthetic nutrients are almost chemically identical to those found in food. However, the production process of synthetic nutrients is very different to the way plants and animals create them. So despite having a similar structure, your body may react differently to synthetic nutrients. Additionally, it’s unclear how well synthetic nutrients are absorbed and used in the body. Some may be more easily absorbed, not others (3Trusted Source). This is because when you eat real food, you’re not consuming single nutrients, but rather a whole range of vitamins, minerals, co-factors and enzymes that allow for optimal use by the body. Without these additional compounds, synthetic nutrients are unlikely to be used by the body in the same way as their natural counterparts (4Trusted Source). For example, studies show that natural vitamin E is absorbed twice as efficiently as synthetic vitamin E (5Trusted Source).

Natural whole foods may help manage and prevent heart disease, diabetes, cancer and early death. These benefits have been linked to the wide range of vitamins, minerals, antioxidants, fiber and fatty acids found in whole foods.

Fruits and Vegetables

Fruits and vegetables provide us with fiber, vitamins, minerals and plant compounds, which are thought to be responsible for many health benefits. Observational studies show that higher fruit and vegetable intake is linked to a lower risk of heart disease, cancer, diabetes, arthritis and some brain disorders (6Trusted Source, 7Trusted Source, 8Trusted Source). Increased fruit intake is also linked to lower blood pressure, reduced oxidative stress and improved blood sugar control (9Trusted Source, 10Trusted Source). One review found that for each daily portion of fruit or vegetables consumed, the risk of heart disease decreased by 4–7% (11Trusted Source).

Oily Fish

Scientists believe that the high levels of omega-3 fatty acids in oily fish are responsible for improved heart health. Many large observational studies have shown that people who eat fish regularly have a lower risk of heart attacks, strokes and death from heart disease (12Trusted Source, 13Trusted Source, 14Trusted Source, 15Trusted Source). One study of more than 40,000 males aged 40–75 found that those who regularly ate one or more servings of fish per week had a 15% lower risk of heart disease (16Trusted Source).

Beans and Legumes

Experts believe that the high soluble fiber content and the wide range of vitamins, minerals and antioxidants in beans and legumes may help reduce the risk of heart disease, diabetes and certain cancers (17Trusted Source, 18Trusted Source, 19Trusted Source). Eating one serving of legumes like beans, peas and chickpeas each day has been linked to 5% lower LDL cholesterol levels and a 5-6% lower risk of heart disease (20Trusted Source).

Nuts and Seeds

Nuts and seeds are high in antioxidants, minerals and healthy fats. They have been associated with a reduced risk of early death, heart disease and diabetes (21Trusted Source, 22Trusted Source). One review found that 4 weekly servings of nuts was linked to a 28% lower risk of heart disease, and 22% lower risk of diabetes (22Trusted Source).

Whole Grains

Whole grains contain many valuable nutrients, including fiber, B vitamins and minerals such as iron, magnesium and selenium. Whole grain consumption has also been associated with protection against cancer, heart disease, diabetes and obesity (23Trusted Source).

Although it’s clear that natural nutrients are associated with many health benefits, the evidence for synthetic supplements is mixed.

Multivitamins

Some observational studies have found multivitamin use to be associated with a lower risk of heart disease and cancer (24Trusted Source, 25Trusted Source, 26Trusted Source, 27Trusted Source, 28Trusted Source). However, other studies have found no effect (29Trusted Source, 30Trusted Source, 31Trusted Source, 32Trusted Source, 33Trusted Source, 34Trusted Source). Some even link multivitamin use to increased cancer risk (35Trusted Source, 36Trusted Source, 37Trusted Source, 38Trusted Source).

One large study looked into the effects of a high-dose multivitamin on heart health. After almost 5 years, the study found that multivitamins had no beneficial effect (39Trusted Source).

However, several other studies have linked multivitamin supplements to improved memory in older adults (40Trusted Source, 41Trusted Source, 42Trusted Source, 43Trusted Source). Nevertheless, the Physicians’ Health Study II found that 12 years of daily multivitamin use did not affect brain function or memory for men over 65 (44Trusted Source).

Single and Paired Vitamins

One review found no clear evidence that single or paired supplements benefit heart disease (45Trusted Source). However, some previous studies suggest that B vitamins like folic acid may improve brain function (46Trusted Source). Yet other strong studies report that dietary supplements, including B vitamins, do not improve brain function (47Trusted Source, 48Trusted Source).

Despite knowing that adequate vitamin D levels are critical for good health and disease prevention, vitamin D supplements are also under much scrutiny (49Trusted Source, 50Trusted Source). Vitamin D supplements have been linked to numerous benefits related to cancer, bone health and brain function, to name a few. Yet experts agree more evidence is needed (50Trusted Source, 51Trusted Source). One thing experts generally agree on is that vitamin D supplements, when combined with calcium, can improve bone health in older people (50Trusted Source).

Antioxidants

Several reviews have found no evidence to support antioxidant supplements, including beta-carotene, vitamins A, C, E, and selenium (alone or in combination) for reduced risk of death and cancer (52Trusted Source, 53Trusted Source). In fact, beta-carotene supplements have been shown to increase the risk of cancer in smokers (54Trusted Source). Nonetheless, antioxidant vitamins and minerals may help slow down the progression of diseases that cause blindness. However, more research is needed (55Trusted Source, 56Trusted Source).

There is no clear evidence to suggest that most synthetic nutrients are beneficial for healthy, well-nourished people.

However, there are certain groups who may benefit from supplementing with synthetic nutrients. These include:

• The elderly: This group tends to be at a higher risk of vitamin D deficiency and may also need more vitamin B12 and calcium for bone health (57Trusted Source, 58Trusted Source).
• Vegans and vegetarians: As certain vitamins and minerals are found mainly in animal products, this group is often at a high risk of deficiency for vitamin B12, calcium, zinc, iron and vitamin D (59Trusted Source, 60Trusted Source).
• Pregnant and breastfeeding women: These women may have to supplement their diet with extra vitamins and/or minerals (such as vitamin D) and avoid others (such as vitamin A) (61Trusted Source).
• Women of childbearing age: This group is often encouraged to take a folic acid supplement to reduce the risk of neural tube defects if they do become pregnant. However, taking more than you need may have some risks.
• People with nutrient deficiencies: Certain dietary supplements may treat nutritional deficiencies, such as iron supplements for treating iron deficiency anaemia (62Trusted Source).

In general, taking supplements according to the amounts directed on the package is safe for most people. However, the FDATrusted Source does not review dietary supplements for safety and effectiveness before they are marketed. Therefore, supplement fraud can occur. This means that supplements can contain more or less nutrients than stated on the label. Others may contain substances not listed on the label.

If you already consume a wide range of nutrients through your diet, taking extra supplements can exceed the recommended daily intake of many nutrients. When taken in excess, water-soluble vitamins like vitamin C and B vitamins are flushed out of the body through your urine. However, fat-soluble vitamins — vitamins A, D, E, and K — may be stored in the body. This means that there is a risk of them accumulating to high levels, leading to hypervitaminosis.

Pregnant women need to be especially careful with their vitamin A intake, as excess amounts have been linked to birth defects (63Trusted Source). Results from many clinical trials show that beta-carotene, vitamin E, and possibly high doses of vitamin A can increase the risk of premature death (64Trusted Source, 65Trusted Source).

Other studies have linked multivitamin use to increased cancer risk, and iron supplements can be harmful for people who don’t need them (66Trusted Source, 67Trusted Source, 68Trusted Source, 69Trusted Source). There is also some evidence that synthetic folic acid is more harmful than the natural folate in foods. It may build up in the body and raise the risk of cancer (70Trusted Source, 71Trusted Source, 72Trusted Source).