5Possible Side Effects of Probiotics

Probiotics are living bacteria and yeasts that provide health benefits when consumed in large amounts.

这y can be taken as supplements or consumed naturally through fermented foods like yogurt, kefir, sauerkraut, kimchi and kombucha ( 1 ，，，， 2 ，，，， 3 ，，，， 4 ）。

这health benefits of probiotic补充剂和食物已得到充分记录，包括较低的感染风险，改善消化，甚至降低了某些慢性疾病的风险（ 5 ，，，， 6 ，，，， 7 ，，，， 8 ）。

While there are many health benefits linked to taking probiotics, there can also be side effects. Most of these are minor and only affect a small percentage of the population.

However, some people with serious illnesses or compromised immune systems may experience more severe complications.

This article reviews the most common side effects of probiotics and how to reduce them.

虽然大多数人没有副作用，但最常见的对基于细菌的益生菌补充剂的反应是暂时增加气体和腹胀（（ 9 ）。

Those taking yeast-based probiotics may experience constipation and increased thirst ( 10 ）。

尚不清楚为什么有些人会遇到这些副作用，但是在继续使用几周后，他们通常会消退（ 9 ）。

To reduce the likelihood of side effects, start with a low dose of probiotics and slowly increase to the full dosage over a few weeks. This can help your body adjust to them.

如果气体，腹胀或任何其他副作用持续了几周以上，请停止服用益生菌并咨询医疗专业人员。

Summary

有些人开始服用益生菌时，气体，腹胀，便秘或口渴会增加。这些副作用应在几周内消失。

Someprobiotic-rich foods，，，，like yogurt, sauerkraut and kimchi, contain biogenic amines (11，，，， 12 ）。

Biogenic amines are substances that form when protein-containing foods age or are fermented by bacteria ( 13 ）。

这most common amines found in probiotic-rich foods include histamine, tyramine, tryptamine and phenylethylamine ( 14 ）。

Amines can excite the central nervous system, increase or decrease blood flow and may trigger headaches in people sensitive to the substance ( 15 ，，，， 16 ）。

One study found that low-histamine diets reduced headaches in 75% of participants. However, a review of 10 controlled studies found no significant effect of dietary amines on headaches ( 17 ，，，， 18 ）。

需要更多的研究来确定胺在某些人中是否可以直接触发头痛或偏头痛。

Keeping a food diary including any headache symptoms you might experience can help clarify whether fermented foods are problematic for you.

如果富含益生菌的食物触发您的症状，则益生菌补充剂可能是一个更好的选择。

Summary

Fermented foods rich in probiotics naturally contain amines. Some people may experience headaches after eating these foods, and should instead opt for probiotic supplements.

Some bacterial strains used in probiotic supplements can produce histamine inside the digestive tract of humans ( 19 ，，，， 20 ，，，， 21 ）。

Histamine is a molecule that is normally produced by your immune system when it detects a threat.

组胺水平升高时,血管扩张to bring more blood to the affected area. The vessels also become more permeable so that immune cells can easily get into the relevant tissue to combat any pathogens ( 22 ）。

这一过程创造了红肿的ffected area, and can also trigger allergy symptoms such as itching, watery eyes, runny nose or trouble breathing.

Normally, histamine that is produced in your digestive tract is naturally degraded by an enzyme called diamine oxidase (DAO). This enzyme inhibits histamine levels from rising enough to cause symptoms ( 23 ）。

但是，有些患有组胺不耐受的人难以正确地分解身体中的组胺，因为他们没有产生足够的dao（ 24 ，，，， 25 ，，，， 26 ）。

然后，多余的组胺通过肠道的衬里吸收到血液中，引起类似于过敏反应的症状（ 27 ）。

People with a histamine intolerance should avoid foods that contain excess histamine ( 28 ）。

从理论上讲，他们可能想选择不含含有组胺的细菌的益生菌补充剂，但迄今为止，尚无对该特定区域的研究。

一些产生组胺的益生菌菌株包括Lactobacillus buchneri, Lactobacillus helveticus, Lactobacillus hilgardiiandStreptococcus thermophilus（（ 29 ，，，， 30 ，，，， 31 ）。

Summary

一些益生菌可以在消化道内产生组胺。患有组胺不耐受的人可能希望避免这些细菌菌株。

People with过敏或不耐受应该仔细阅读益生菌补充剂的标签，因为它们可能包含可以反应的成分。

For example, some of the supplements contain allergens such as dairy, egg or soy.

任何过敏反应的人都应避免这些成分，因为它们可能会引发过敏反应。如有必要，请仔细阅读标签以避免这些成分（ 32 ）。

Similarly, yeast-based probiotics should not be taken by those with yeast allergies. Instead, a bacteria-based probiotic should be used ( 33 ）。

Milk sugar, or lactose, is also used in many probiotic supplements (34）。

While studies suggest that most people with lactose intolerance can tolerate up to 400 mg of lactose in medications or supplements, there have been case reports of adverse effects from probiotics ( 35 ，，，， 36 ，，，， 37 ）。

Since a small number of people with lactose intolerance may experience unpleasant gas and bloating when consuming lactose-containing probiotics, they may want to choose lactose-free products.

In addition to containing powerful probiotics, some supplements also containprebiotics。这se are plant fibers that humans cannot digest, but that bacteria can consume as food. The most common types are lactulose, inulin and various oligosaccharides ( 38 ）。

When a supplement contains both probiotic microorganisms and prebiotic fibers, it is called asynbiotic（（ 39 ）。

有些人在食用合成生物时会经历气体和腹胀。那些经历这些副作用的人可能想选择不含益生元的补充剂（ 40 ）。

Summary

益生菌补充剂可能包含过敏原，乳糖或益生元纤维，可能会导致某些人不良反应。可以通过阅读标签来避免这些成分。

益生菌对绝大多数人口都是安全的，但可能并不适合所有人。

In rare cases, the bacteria or yeasts found in probiotics can enter the bloodstream and cause infections in susceptible individuals ( 41 ，，，， 42 ，，，， 43 ，，，， 44 ）。

Those at greatest risk for infection from probiotics include people with suppressed immune systems, prolonged hospitalizations, venous catheters or those who have undergone recent surgeries ( 45 ，，，， 46 ，，，， 47 ）。

但是，发展感染的风险非常低，并且在普通人群的临床研究中没有严重的感染。

据估计，只有大约一百万的人服用含有益生菌的人Lactobacillibacteria will develop an infection. The risk is even smaller for yeast-based probiotics, with only about one in 5.6 million users getting infected ( 48 ，，，， 49 ）。

When infections do occur, they typically respond well to traditional antibiotics or antifungals. However, in rare cases, deaths have occurred ( 48 ，，，， 50 ）。

研究还表明，患有严重急性胰腺炎的人不应服用益生菌，因为这可能会增加死亡的风险（ 51 ）。

Summary

免疫系统，静脉导管，最近的手术，急性胰腺炎或长期住院治疗的人应避免服用益生菌。

益生菌是活生生的生物，可在大量食用时提供健康益处。它们可以作为补品，但也自然地发生发酵食品。

益生菌对大多数人群都是安全的，但是可能会发生副作用。最常见的副作用是气体，腹胀，便秘和口渴的暂时增加。

有些人也对益生菌补充剂或益生菌食品中天然胺的成分的反应不佳。如果发生这种情况，请停止使用益生菌。

在极少数情况下，免疫系统受损，长期住院或最近的手术可能会引起益生菌感染。患有这些条件的人应在食用益生菌之前权衡风险和利益。

Overall, probiotics are a beneficial addition to most people’s diet orsupplementregimen, with relatively few and unlikely side effects.