This rare disease requires a limit on meat, eggs and beans. How can we supplement them in our daily life?

Methylmalonic aciduria (MMA), also known as methylmalonic acidemia, is the most common rare disease among organic acid metabolism disorders in my country. The prevalence of MMA in my country varies greatly in different regions, ranging from 1/4000 to 1/50,000, with an average of about 1/15,000.

Since methylmalonic acid is a metabolite of methylmalonyl-CoA in the catabolic pathway of isoleucine, valine, methionine (methionine), threonine, cholesterol and odd-chain fatty acids, we generally need to pay attention to the intake of relevant nutrients during the treatment of MMA, especially the control of protein foods rich in isoleucine, valine, methionine, threonine, etc.

1. Content of isoleucine, valine, methionine and threonine in common foods

Generally speaking, isoleucine mainly comes from foods such as liver, eggs, duck eggs, soybeans, black beans, corn, black rice, brown rice, almonds, peanuts, wheat, fish, and dairy products; valine mainly comes from meat, dairy products, dry beans, nuts, etc.; methionine mainly comes from soybeans, black beans, green beans, eggs, duck eggs, fish, pork, beef, etc.; threonine mainly comes from animal liver, meat, eggs, mushrooms, etc.

Of course, in order to have a clearer understanding of the content of the above four amino acids in specific foods, we can check the content of amino acids in common foods in the "Chinese Food Composition Table: Standard Edition".

2. Precautions for dietary treatment

Dietary treatment is particularly important for patients with simple MMA, mainly adjusting the intake of natural protein according to the patient's condition and blood ammonia situation. However, while limiting natural protein, we should also pay attention to the following matters to avoid affecting growth and development.

1. While strictly controlling natural food intake, special formula milk powder that does not contain isoleucine, valine, methionine, and threonine can be supplemented under guidance to ensure energy and protein intake.

2. In order to ensure adequate energy intake, you can choose foods with relatively low protein content, such as lotus root powder, maltodextrin, sugar, fruit puree, melons, fruits and vegetables, etc., and at the same time increase the intake of fats and oils appropriately.

3. You can choose commercially available low-protein foods, such as low-protein rice, low-protein flour, low-protein biscuits, cornstarch, etc., and make them into a variety of staple foods or snacks to increase energy intake.

4. Considering that isoleucine, valine and methionine are essential amino acids for the human body and cannot be restricted for a long time, it is necessary to monitor the levels of isoleucine, valine and methionine regularly to avoid deficiency.

5. Pay attention to the measurement of height and weight, and monitor growth and development.

In general, protein intake is particularly critical for children with MMA, and different requirements are required under different disease states and age groups. However, whether it is special formula milk powder, natural food, or processed low-protein food, the family members of the children should carefully learn and master the calculation method of protein in food under the guidance of doctors and nutritionists, so as to ensure that the children can complete the corresponding protein intake at home according to the doctor's instructions, and regularly visit the pediatric endocrinology department and clinical nutrition department for outpatient follow-up to adjust the treatment and nutrition plan.

References:

[1] Feng Zhichun, Wang Yan, Yang Rulai. Theory and practice of prevention of genetic metabolic diseases[M]. Beijing: People's Medical Publishing House, 2023.

[2] Some pictures are from the Internet.

Author: Niu Yang, Feng Yi, Sheng Jinye, Lu Wenwei, Mao Xiaomeng

Instructors: Cai Wei, Tang Qingya

Department of Clinical Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine

Project source: Shanghai Health Science Popularization Youth Talent Project (JKKPYC-2022-06)