How much do you know about lactose intolerance?

This is the 4802nd article of Da Yi Xiao Hu

Situational dialogue

Patient : Doctor, I have drunk milk tea several times recently. Every time I drink milk tea, I will have symptoms of bloating, diarrhea, and headache, but this did not happen before when I drank milk tea.

Doctor : So every time you drink milk tea and have gastrointestinal symptoms, do they subside on their own?

Patient : It can be relieved. Today I couldn’t help but ordered milk tea, and I ended up having diarrhea again…

Doctor : It may be lactose intolerance..., I suggest...

1. What is lactose intolerance

Lactose intolerance (LI) is not an allergic phenomenon. It is caused by the lack of lactase (LT). The lactose ingested by the human body needs to be broken down into monosaccharides by intestinal lactase before it can be absorbed. In the case of lactase deficiency, the lactose ingested by the body cannot be broken down and absorbed, causing digestive symptoms such as diarrhea, which is called lactose intolerance. According to the cause, the American Academy of Pediatrics divides lactose into four types: congenital, primary, secondary and developmental.

2. Clinical manifestations

The lactase in the small intestine breaks down lactose into glucose + galactose. When the body lacks lactase, lactose cannot be broken down and absorbed and will go straight to the colon, where it will ferment under the action of intestinal flora to produce lactic acid and a large amount of gas (hydrogen, methane, carbon dioxide, etc.). Lactic acid will stimulate and increase intestinal peristalsis, causing diarrhea, and gas will produce bloating in the intestine, occasionally inducing intestinal colic.

In addition, some people experience memory loss, musculoskeletal pain, arrhythmia, depression, anxiety, ulcers, disrupted menstrual cycles, acne, increased urination frequency, eczema and other allergic diseases (sinusitis, rhinitis).

3. The dangers of lactose intolerance

(1) Infancy

In the early stage, it may cause vomiting, diarrhea, constipation, bowel sounds, abdominal distension, abdominal pain, flatulence and other problems;

Long-term lactose intolerance can easily lead to chronic diarrhea in children, which is difficult to cure. Some children may develop diaper rash. In severe cases, it can affect the brain development of infants and young children.

(2) Adulthood

Lactose-intolerant patients will limit their consumption of milk and dairy products, thereby reducing their intake of nutrients such as high-quality protein and calcium.

4. Why did lactose intolerance appear in adulthood if I didn’t have it before?

In infancy, the body secretes enough lactase to better digest breast milk. However, as we age, the ability to synthesize and secrete lactase will gradually "degenerate". If we suddenly consume dairy products containing a large amount of lactose, we will experience symptoms of lactose intolerance.

5. How to treat lactose intolerance

(1) Appropriately control the intake of dairy products

It is not recommended to completely restrict the intake of dairy products. Most people with lactose intolerance can tolerate 12-15 grams of lactose per day.

Infants and young children prefer lactose-free or low-lactose milk with added lactase;

Choose yogurt products, because during the fermentation process of yogurt, the β-galactosidase of lactic acid bacteria breaks down part of the lactose, which significantly reduces the lactose content in the yogurt, making it suitable for people with lactose intolerance.

Do not drink on an empty stomach;

Pay attention to the drinking temperature and heat it appropriately;

Develop a habit of drinking dairy products continuously;

(2) Supplementing nutrients (such as calcium and vitamin D) and protein from non-dairy sources

The report states that patients with lactose intolerance consume less milk calcium, leading to reduced bone density and increased fractures. Although this association has not been effectively confirmed, people with lactose intolerance can appropriately supplement with some calcium and vitamin D, depending on whether you do not consume dairy products at all.

(3) Drug treatment

Bifidobacterium preparations: Bifidobacterium has lactase activity, can hydrolyze lactose, and can improve symptoms. It can assist in the treatment of lactose intolerance in infants and young children. Bifidobacterium triple live bacteria tablets/powders are recommended.

Lactase preparations: The root cause of lactose intolerance is lactase deficiency or low activity. Theoretically, the most ideal treatment is to supplement lactase preparations. Enzymes are available in gel, liquid, capsule or tablet form, such as lactase triple preparations.

VI. Conclusion

Generally speaking, children with lactose intolerance whose symptoms are not obvious generally do not need special treatment. Lactose intolerance in adults is mainly caused by excessive lactose intake at one time, such as drinking milk tea containing lactose. A report on "Is there milk and tea in milk tea?" found that only a small number of milk teas sampled met the milk content standards, which means that there may not be real "milk" in the milk tea, but "creamer". Therefore, when buying milk tea, you can read the ingredient list carefully or ask the store clerk whether it contains fresh milk. Although milk tea containing "creamer" will not cause lactose intolerance, it has a low protein content and a high added sugar content, and it is not recommended for long-term drinking.

References:

[1] Hou Ancun. Advances in diagnosis and treatment of lactose intolerance[J]. Journal of Clinical and Experimental Medicine, 2017, 16(02): 204-207.

[2] Szilagyi A, Ishayek N. Lactose Intolerance, Dairy Avoidance, and Treatment Options. Nutrients. 2018 Dec 15;10(12):1994.

[3] Catanzaro R, Sciuto M, Marotta F. Lactose intolerance: An update on its pathogenesis, diagnosis, and treatment. Nutr Res. 2021 May; 89:23-34.

[4] Jiao Qiang, Liu Zhiyong, Guo Yi. Research progress of lactase preparations[J]. Henan Journal of Preventive Medicine, 2019, 30(04): 275-278.

[5] Chen Ni, Zhou Na, Huang Lin. Is there milk and tea in milk tea? [N]. Xiamen Daily, 2023-11-09(A09).

Author: Shanghai Sixth People's Hospital

Zhang Manman