Breastfeeding and Maternal/Child Vitamin B12 Deficiency
by Anne Eglash MD, IBCLC, FABM
Vitamins are nutritional substances that our bodies usually cannot make on their own, and are required for our bodies to function properly. Vitamin B12 is essential for proper red cell function, neurologic function, and DNA synthesis. Mothers may be at risk for low vitamin B12 for a variety of reasons. Maternal diet plays a very important role in vitamin B12 status. Dietary sources of vitamin B12 include animal proteins such as chicken, eggs, red meat, fish, and dairy products. Some substances are fortified with B12 such as cereals, nondairy milks, and nutritional yeast (brewer’s yeast). Women who are vegan or vegetarian are at significant risk for vitamin B12 deficiency. Low vitamin B12 can be due to certain medications that decrease vitamin B12 absorption, such as anti-acid medications, especially proton pump inhibitors (e.g. omeprazole, lansoprazole, etc.), and metformin which is most often taken for type 2 diabetes and polycystic ovarian syndrome. Intestinal surgery may decrease vitamin B12 absorption, such as gastric bypass surgery. Certain other health conditions, such as celiac sprue, Crohn’s disease, and pernicious anemia, make it difficult to absorb vitamin B12 from the diet. The Academy of Nutrition and Dietetics recommends supplemental vitamin B12 for vegans and lacto-ovo vegetarians during pregnancy and lactation to make sure that the fetus/nursing infant has sufficient vitamin B12.
The article for this week reports on 13 cases of infants with vitamin B12 deficiency, describing their clinical presentations and in particular their abnormal movements. The abnormal movements were quite varied, and included eyelid twitching and involuntary muscle contractions in various parts of the body. The involuntary contractions happened several times a day or a week. Several of the infants had low tone of the neck or trunk. A few of the 13 infants had a delay in social smile and insufficient eye contact.
- Neurologic problems in infants with vitamin B12 deficiency often improve and gradually resolve with vitamin B12 supplementation.
- Mothers may not have any symptoms of a borderline low or low vitamin B12 level.
- When replacing vitamin B12 for infants, they must be given the B12 as shots rather than orally.
- A high dose of vitamin B12, such as 1000 times the recommended daily intake, is considered safe.
See the Answer
Abnormal movements such as tremor, myoclonus, and choreoathetosis due to infantile nutritional vitamin B12 (Cbl, cobalamin) deficiency or after Cbl injection have been recognized for many years. However, nutritional Cbl deficiency may be more common than recognized and a variety of the abnormal movements may be beyond our estimates.
To define the relationship between a large variety of abnormal movements in infants and vitamin B12 deficiency even if serum vitamin B12 levels and/or examination are normal.
Materials and Methods
This study analyzed a variety of abnormal movements such as involuntary eye movements, limb and body contractions, and gasping as well as clinical, metabolic, radiologic, and treatment results in 13 infants with nutritional Cbl deficiency. This is a retrospective study based on observation and experience.
This study included 13 infants (11 boys and 2 girls) with a large spectrum of abnormal movements, the mean age at admission was 8.3 months with a range of 3–22 months. All patients were breastfeeding. In seven cases and their mother’s serum vitamin B12 levels were below 200 pg/ml. About one-third of cases serum vitamin B12 levels were over 200 pg/ml. Clinically, mild hypotonia was present in 5 cases, inadequate social interactions in 2 cases, and sensorineural hearing loss in one case. Brain MRI showed frontotemporal enlarged subarachnoid spaces and thinning of the corpus callosum in two cases. EEG examinations were normal in all cases at admission. All cases recovered rapidly within one month with treatment.
Nutritional Cbl deficiency is a treatable disease that should be considered in the etiology of a variety of movement abnormalities in infants even if serum vitamin B12 values and neurological development are normal.
When replacing vitamin B12 for infants, it can be given orally rather than as shots, as long as there is no reason for poor absorption, such as taking certain medications or having had GI surgery.
Low vitamin B12 is a very common problem in primary care practice, and I have to agree with the authors that many adults have low levels, such as under 250-300 ng/ml, and often don’t have classic symptoms of fatigue, depression, or tingling/numbness in the fingers and toes, or other neurologic complaints. The message here is that infants may be observed to have intermittent muscle twitches and contractions, and if they are mild, could be missed or passed off for something benign, never having their vitamin B12 level checked.
Therefore, it is important to screen pregnant and breastfeeding mothers for risk factors of low B12, such as vegan and vegetarian diets, a history of GI surgery, or known GI illness, to take extra B12, such as 120-250mcg daily or follow their vitamin B12 levels. The recommended daily allowance during pregnancy and lactation is 2.6-2.8mcg. The supplement doses are high, often 250mcg-5000mcg, because only a small percent of the supplement dose is typically absorbed. It is not typically a problem if the supplement raises the vitamin B12 level above normal.