B-Complex Vitamins: Benefits, Side Effects and Dosage

B维生素是a group of nutrients that play many important roles in your body.

Most people get the recommended amounts of these vitamins through diet alone since they are found in a wide variety of foods.

However, factors like age, pregnancy, dietary choices, medical conditions, genetics, medication and alcohol use increase the body’s demand for B vitamins.

在这种情况下，可能需要补充B维生素。

Nutritional supplements that contain all eight B vitamins are referred to as B-complex vitamins.

Here are the health benefits of B-complex vitamins as well as dosage recommendations and potential side effects.

What Are B-Complex Vitamins?

B-complex supplements usually pack all eight B vitamins into one pill.

B维生素是水溶性，这意味着您的身体不会存储它们。因此，您的饮食必须每天供应它们。

B维生素具有许多重要的功能，对维持健康至关重要。

B-复杂的维生素通常包含以下内容：

• B1 (thiamine):Thiamine plays an essential role in metabolism by helping convert nutrients into energy. The richest food sources include pork, sunflower seeds and wheat germ ( 1 ).
• B2（核黄莲）：Riboflavin helps convert food into energy and also acts as an antioxidant. Foods highest in riboflavin include organ meats, beef and mushrooms ( 2 ).
• B3 (niacin):烟酸在细胞信号，代谢和DNA生产和修复中起着作用。食物来源包括鸡，金枪鱼和扁豆（ 3. ).
• B5 (pantothenic acid):Like other B vitamins, pantothenic acid helps your body obtain energy from food and is also involved in hormone and cholesterol production. Liver, fish, yogurt and avocado are all good sources (4.).
• B6（吡哆醇）：Pyridoxine is involved in amino acid metabolism, red blood cell production and the creation of neurotransmitters. Foods highest in this vitamin include chickpeas, salmon and potatoes (5.).
• B7（生物素）：Biotin is essential for carbohydrate and fat metabolism and regulates gene expression. Yeast, eggs, salmon, cheese and liver are among the best food sources of biotin ( 6. ).
• B9（叶酸）：Folate需要进行细胞生长，氨基酸代谢，形成红色和白细胞和适当的细胞分裂。它可以在食材植物，肝脏和豆类等食物中找到或补充剂作为叶酸（ 7. ).
• B12 (cobalamin):也许是最着名的所有B族维生素，B12对神经功能，DNA生产和红细胞发育至关重要。B12天然在肉类等动物来源中发现，eggs那seafood and dairy ( 8. ).

虽然这些维生素有一些相同的特点那they all have unique functions and are needed in different amounts.

Summary

B-复合体补充剂通常含有所有八个B维生素，方便地填充成一粒丸。

谁应该服用B-复合维生素？

Since B vitamins are found in many foods, you are most likely not at risk of developing a deficiency as long as you follow a well-rounded diet.

However, certain circumstances increase the need for B vitamins, making supplements necessary.

怀孕或母乳喂养女性

怀孕期间，对B维生素，特别是B12和叶酸的需求，增长以支持胎儿发育（ 9. ).

In women who arepregnant或母乳喂养，特别是那些遵循素食或素食饮食的人，补充B-复合维生素是至关重要的。

B12 or folate deficiency in pregnant or breastfeeding women can lead to severe neurological damage or birth defects in the fetus or infant ( 10. ).

Older Adults

As you age, your ability to absorb vitamin B12 decreases and your appetite declines, making it difficult for some people to get enough B12 through diet alone.

The body’s ability to release B12 from food so that it can be absorbed depends on adequate amounts of stomach acid.

然而，估计，10-30％的人超过50人不会产生足够的胃酸来适当吸收B12（ 11. ).

缺乏B12与老年人的抑郁症和情绪紊乱的速度提高（ 12. 那 13. ).

Deficiencies in vitamin B6 and folate are also common in the elderly population ( 14. 那 15. ).

那些具有某些医疗条件的人

People with certain medical conditions, such as celiac disease, cancer, Crohn’s disease, alcoholism, hypothyroidism and anorexia, are more susceptible to developing nutrient deficiencies, including B vitamins ( 16. 那 17. 那 18. 那 19. 那 20. ).

Additionally, the MTHFR genetic mutation can affect how your body metabolizes folate and can lead to a folate deficiency and other health issues ( 21. ).

What’s more, people who have undergone certain weight-loss surgeries are also more likely to be deficient in B vitamins ( 22. ).

In these circumstances, patients are often advised to supplement with a B-complex vitamin to correct or avoid deficiencies.

素食主义者和素食主义者

Vitamin B12 is naturally found in animal products like meat, dairy, eggs and seafood.

如果通过强化食品或补充剂（ 23. ).

每日B-复合体维生素可以帮助确保选择遵循消除动物产品的饮食的人足够的这些重要的营养素。

People Taking Certain Medications

Commonly prescribed medications can lead to a deficiency in B vitamins.

For example, proton pump inhibitors, which are medications that lower stomach acid, can decrease the absorption of B12, while metformin, a popular diabetes drug, can decrease levels of both B12 and folate ( 24. 那 25. ).

Birth control pills can also deplete several B vitamins, including B6, B12, folate and riboflavin ( 26. ).

Summary

怀孕，医疗条件，手术，遗传突变，药物，饮食限制和年龄都会影响您的身体如何吸收和使用B维生素。

Health Benefits of Taking B-Complex Vitamins

While certain conditions make it necessary for some people to supplement with B-complex vitamins, research has shown that taking a B-complex supplement may be helpful even for people who don’t have an increased need for these nutrients.

May Reduce Stress and Boost Mood

B-复杂的维生素通常用于减少疲劳和促进情绪。

一些研究表明，B-复合体维生素可以提升您的精神，提高您的认知性能。

A 33-day study in 215 healthy men found that treatment with a high-dose B-complex and mineral supplement improved general mental health and stress and enhanced performance on cognitive tests ( 27. ).

Another study in young adults showed that supplementing with a multivitamin containing high levels of B-complex vitamins for 90 days reduced stress and mental fatigue ( 28. ).

可能会减少焦虑或抑郁症的症状

虽然B-复杂的维生素补充剂不是治疗心理健康问题，但它们可能有所帮助改善抑郁或焦虑的症状。

60名患有抑郁症的成人的研究表明，与安慰剂（ 29. ).

B维生素还可以在与抗抑郁药物组合给药时增强治疗响应。

一项研究发现，与安慰剂相比（ 30. ).

Note that low blood levels of certain B vitamins, including B12, B6 and folate, have been linked to an increased risk of depression, which is why it’s important to rule out nutrient deficiencies if you are experiencing symptoms of depression ( 31. 那 32. ).

Summary

B-complex supplements may relieve stress, boost cognitive performance and reduce symptoms of depression and anxiety, even in people without B vitamin deficiencies.

Recommended Dosage

Each B vitamin has a specific recommended daily amount that varies depending on gender, age and other variables like pregnancy.

For women and men, the recommended daily intake (RDI) for B vitamins are as follows:

Pregnant and lactating women need higher amounts of B vitamins, while infants and children need less ( 33. ).

If you are deficient in B vitamins, you may need to supplement with higher doses to correct the deficiency.

For these reasons, it’s important to choose a B-complex supplement based on your individual requirements for each B vitamin.

根据您的年龄和健康，与您的医生与您的医生交谈。

Summary

Recommended intake for B vitamins varies depending on age, nutrient demands, gender and health status.

潜在的副作用

Since B vitamins are water-soluble, it’s unlikely that you will consume too much of these nutrients through diet alone or by taking a B-complex supplement as directed.

However, taking supplements that contain excessively high and unnecessary quantities of B-complex vitamins could lead to serious side effects.

High doses of supplemental B3 (niacin) may lead to vomiting, high blood sugar levels, skin flushing and even liver damage ( 34. ).

Additionally, high doses of B6 can cause nerve damage, light sensitivity and painful skin lesions ( 35 ).

Another side effect of B-complex supplements is that it can turn urine bright yellow.

Although discolored urine can be shocking, it’s not dangerous but simply your body getting rid of excess vitamins that it can’t use.

If you need to take a B-complex supplement, always choose reputable brands that volunteer to have their products independently tested by organizations like the US Pharmacopeial Convention (USP).

Summary

虽然按照指示服用B复合补充剂可能是安全的，但消耗高剂量的B3或B6可能导致严重的副作用。

The Bottom Line

Pregnant women, older adults, vegans and those with certain medical conditions may benefit from taking a B-complex supplement.

服用这些补充剂也可能改善情绪，认知功能和抑郁症状。

如果您遵循推荐的剂量，则不太可能效果，这取决于年龄，营养需求，性别和健康。

If you aren’t sure if taking a B-complex supplement will benefit your health, speak with your doctor to help you determine if it’s the right choice for you.

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Purchase B-complex supplements online.

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