🥄 Reasons for recommending early resumption of feeding
To prevent dehydration and malnutrition, it is recommended to return to a normal diet appropriate for the age as soon as vomiting subsides. Continuing a restricted diet may delay recovery.

🍗 Protein intake is important
Proteins such as meat, fish, eggs, and tofu contribute to the repair of the intestinal lining and the recovery of immune function. A diet consisting only of rice porridge and miso soup may be nutritionally insufficient.

🥛 Handling of dairy products
Milk and yogurt can be safely consumed in amounts of about 200 ml in many cases. Lactose intolerance, severe cases, and infants (especially under 6 months old) require individual attention.

For infants, continued breastfeeding is most appropriate.

📚 References

1. Shane AL, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis. 2017;64(3):e1–e50.
2. Flynn TG, et al. Viral Gastroenteritis. The Lancet. 2024;403(10391):112–124.
3. Thielman NM, Guerrant RL. Acute Infectious Diarrhea. N Engl J Med. 2004;350(1):38–47.
4. Sullivan PB. Nutritional Management of Acute Diarrhea. Nutrition. 1998;14(1):7–12.
5. Thapar N, Sanderson IR. Diarrhea in Children: An Interface Between Developing and Developed Countries. Lancet. 2004;363(9409):641–653.
6. Burkhart DM. Management of Acute Gastroenteritis in Children. Am Fam Physician. 1999;60(1):255–264.

🥛 Lactose Intolerance in Japanese People and Milk Consumption: How to Live Well with Your Constitution

Many Japanese people have a genetic predisposition in which the activity of the lactase enzyme—which breaks down lactose—declines in adulthood, and lactose intolerance is common. However, not everyone experiences symptoms.

🧬 Characteristics of lactose intolerance in Japanese people
Approximately 90% of Japanese people are lactose intolerant, meaning they have a reduced ability to digest lactose. This is a genetic trait caused by their LCT genotype.

No entry The presence or absence of symptoms varies greatly from person to person.
Many people with lactose intolerance do not experience symptoms with about 200 ml of milk (approximately 10 g of lactose), and tolerance increases when consumed with food.

🦠 Improved tolerance due to adaptation of the gut microbiota
It has been reported that continuous lactose intake increases intestinal bacteria such as Bifidobacterium and improves lactose metabolism.

🍶 Yogurt is relatively well-tolerated.
Lactic acid bacteria contained in yogurt break down lactose, so it is said that people with lactose intolerance are less likely to experience symptoms. Combining prebiotics and probiotics is also effective.

Scales of justice Starting with a small dose and observing the progress is fundamental.
It is recommended to start with a small dose and adjust it according to individual tolerance, while monitoring for the presence of symptoms.

📚 References

1. Kato K, et al. Association Between Functional Lactase Variants and a High Abundance of Bifidobacterium in the Gut of Healthy Japanese People. PLoS One. 2018;13(11):e0206189.
2. Nose O, et al. Breath Hydrogen Test for Detecting Lactose Malabsorption in Infants and Children: Prevalence of Lactose Malabsorption in Japanese Children and Adults. Arch Dis Child. 1979;54(10):760–765.
3. JanssenDuijghuijsen L, et al. Changes in Gut Microbiota and Lactose Intolerance Symptoms Before and After Daily Lactose Supplementation in Individuals With the Lactase Nonpersistent Genotype. Am J Clin Nutr. 2024;119(2):456–468.
4. Forsgård RA. Lactose Digestion in Humans: Intestinal Lactase Appears to Be Constitutive Whereas the Colonic Microbiome Is Adaptable. Am J Clin Nutr. 2019;110(4):749–761.
5. Szilagyi A. Adaptation to Lactose in Lactase Non-Persistent Individuals: Effects on Intolerance and the Relationship Between Dairy Food Consumption and Disease Evaluation. Nutrients. 2015;7(9):6751–6779.
6. Shaukat A, et al. Systematic Review: Effective Management Strategies for Lactose Intolerance. Ann Intern Med. 2010;152(12):797–803.
7. Corgneau M, et al. Recent Advances on Lactose Intolerance: Tolerance Thresholds and Currently Available Solutions. Crit Rev Food Sci Nutr. 2017;57(3):354–370.
8. Fassio F, et al. Lactose Maldigestion, Malabsorption, and Intolerance: A Comprehensive Review With a Focus on Current Management and Future Perspectives. Nutrients. 2018;10(11):1599.
9. Misselwitz B, et al. Update on Lactose Malabsorption and Intolerance: Pathogenesis, Diagnosis, and Clinical Management. Gut. 2019;68(11):2080–2091.
10. Savaiano DA. Lactose Digestion From Yogurt: Mechanism and Relevance. Am J Clin Nutr. 2014;99(5 Suppl):1219S–1227S.