Almost everyone knows that eating more fruits and vegetables can supplement vitamins. However, some people don't like to eat fruits and vegetables, or are too busy at work to ensure a balanced diet, so "vitamin supplements" have become a new option.
Can vitamin supplements replace the nutrients in fruits and vegetables?
Life Times invited experts to explain the differences between vitamin supplements and fresh fruits and vegetables, and tell you how to supplement different vitamins.
Experts interviewed
Liu Ailing, researcher at the Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention
Jing Hao, Professor, College of Food Science and Nutritional Engineering, China Agricultural University
Supplements are not a complete substitute for fruits and vegetables
Vitamins are found in very small amounts in the human body, but they play an important role in the process of growth and development, metabolism and so on. However, there is a big difference between simply taking vitamin tablets and supplementing them with food.
Fruits and vegetables contain more than just vitamins
Each fruit and vegetable contains hundreds of ingredients, and each component will cooperate and protect each other, and it is difficult for vitamin supplements with relatively simple ingredients to achieve the health care effect of natural food.
- Rich in dietary fiber. The dietary fiber contained in fruits and vegetables has the effect of promoting intestinal health, preventing constipation, and delaying blood sugar absorption.
- Abundant in inorganic salts. Inorganic salts such as calcium, phosphorus, iron, potassium, and sodium can maintain cell morphology and function, maintain the life activities of organisms, and maintain cell osmotic pressure and acid-base balance.
- Organic acids. The fruit contains the ability to stimulate the body's digestive glands, increase appetite and aid digestion.
- Various enzymes, fungicidal substances and physiologically active ingredients with special functions in vegetables and fruits, as well as phytochemicals such as terpenoids, polyphenols, and plant sterols, play an important role in maintaining human health.
It is recommended that the diet on weekdays should be varied and nutritionally balanced. According to the Dietary Guidelines for Chinese Residents (2022), each person should consume no less than 300 grams of vegetables and 200~350 grams of fresh fruits per day.
May increase the burden on the body
For healthy people, blindly or excessively supplementing a certain nutrient may cause or exacerbate the metabolic disorder of other nutrients and increase the burden on the body.
1. A large intake of liver, cod liver oil or vitamin A supplements can lead to abnormal bone growth, even osteoporosis, and may also cause liver damage.
2. Excessive vitamin C supplementation can lead to nausea and diarrhea, which may increase the risk of kidney stones for people with kidney dysfunction, gout patients and people at high risk of kidney stones.
3. Excessive intake of cod liver oil or vitamin D supplements may cause excessive blood calcium, promote kidney stones, and arteriosclerosis.
4. Vitamin E is less toxic, and a large amount of intake can cause coagulation dysfunction, liver fat accumulation and decreased immune system function.
Vitamins are preferred by dietary supplements
For the general population, fresh fruits and vegetables are the preferred choice for vitamin supplementation, and several common vitamins can be obtained from the following foods.
Vitamin A protects the eyes and fights infections
It is mainly derived from animal liver, milk, poultry eggs, and dark green or red, yellow, and orange vegetables and fruits with high carotenoid content.
B vitamins protect against a wide range of diseases
B vitamins include vitamin B1, vitamin B2, vitamin B12, niacin, folic acid, etc., which are indispensable substances to promote metabolism in the body.
- Vitamin B1 can be supplemented by eating more whole grains, legumes, potatoes and moderate amounts of animal offal.
- Vitamin B2 is widely found in milk, egg yolks, dark green vegetables, cereals, fish and meat, and nuts.
- Niacin (vitamin B3) is mainly a food source of plant seeds and high-quality protein-rich animal foods, especially fish, meat and eggs.
- Folic acid (vitamin B9) is an essential vitamin for trying to conceive. Its food sources are wide, such as green leafy vegetables, legumes, fruits, etc.
- Vitamin B12 is a vitamin that vegetarians and the elderly are more likely to be deficient in, and is found in animal foods, fermented foods and mushroom foods.
Vitamin C anti-aging
It is mainly found in fresh vegetables and fruits, and is usually more abundant in leafy vegetables than in root vegetables. Foods rich in vitamin C, try to eat raw foods that can be eaten raw, such as fruits, onions, lettuce, etc. If your gastrointestinal function is not good, avoid eating raw vegetables.
Vitamin D promotes bone development
The source of vitamin D in food is not abundant, only a few sources such as cod liver oil, liver, whole milk, egg yolk, fatty fish, etc., and more sun exposure is the best source for the human body to obtain sufficient vitamin D.
Vitamin E boosts immunity
There are a wide range of food sources that can be supplemented by intake of vegetable oils and nuts. As long as you eat normally, ensure a certain amount of oil intake every day, such as 20~30 grams of cooking oil, and eat an appropriate amount of nuts, you will usually not lack vitamin E.
Who needs additional supplements
For specific groups of people who are unable to have a balanced diet or have irregular lifestyles, it is necessary to ensure daily intake through vitamin supplements, but they should be supplemented scientifically and curatively under the guidance of professionals.
Women who are trying to conceive or pregnant
Folic acid is especially important for women who are trying to conceive and who are pregnant. Especially in the first few weeks of pregnancy, if the fetus does not receive enough folic acid, fetal neural tube defects such as spina bifida may occur, and the third trimester may lead to anemia in the mother and fetus.
It is recommended that women start daily folic acid supplementation at least 3 months before conception or when they may be pregnant.
People with vision loss
Vitamin A has a great impact on vision, and if the intake is insufficient, the ability to see at night will deteriorate, and even suffer from night blindness and dry eye. Vitamin A supplementation has a certain protective effect on vision.
People with osteoporosis
Both vitamin C and vitamin D play an important role in promoting collagen synthesis and limiting bone resorption. Vitamin D deficiency can lead to mineral abnormalities in bones and teeth, which can lead to osteomalacia and osteoporosis.
It is recommended that people with osteoporosis take daily supplements with these two types of vitamins to reduce the risk of fractures.
People with iron deficiency anemia
The trivalent iron in plant foods cannot be directly absorbed by the body, and vitamin C can convert it into divalent iron, which can be directly absorbed. Vitamin B12 deficiency can also lead to megaloblastic anemia, neurological damage, and cardiovascular disease.
Vitamin supplementation is important to improve iron deficiency anemia and needs to be taken seriously in this population. ▲
Editor of this issue: Wu Mengyao
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