Vitamin D and vitamin B12 deficiencies are common in patients with midgut carcinoid (SI-NET)

Patients with small intestinal neuroendocrine tumours (SI-NET) often have diarrhoea from hormonal overproduction, surgery and medical treatment, leading to malabsorption of bile salts, fats, vitamin B12 and fat-souble vitamins. This could lead to malnutrition.

We assessed nutritional status in 50 consecutive out patients with disseminated SI-NET, 25 patients in each cohort. The first cohort was descriptive and the second cohort supplemented with vitamin D, B12 and calcium. Vitamin D deficiency was defined as <50 nmol/l. All patients were assessed by clinical chemistry and dual-energy X-ray absorptiometry (DXA) and interviewed about weight changes, appetite, gastrointestinal disorders, sunhabits and the use of supplements.

In the first cohort, 29% of the patients were severely and 17% moderately vitamin D deficient. In patients without prior substitution, 32% had subnormal vitamin B12 levels. Seventy-six percent had low bone density. In the second cohort with vitamin and mineral supplementation, none had severe vitamin D deficiency, but 28% had moderate deficiency. No patient had subnormal vitamin B12 levels. Sixty percent had low bone density. The serum levels of vitamin D and B12 were higher and parathyroid hormone (PTH) lower in the second cohort compared with the first cohort (P⩽0,022). Vitamin D and PTH were negatively correlated, r=-30, P=⩽0.036.

Low serum levels of vitamin D and vitamin B12, and low bone density are common in patients with disseminated SI-NET. Supplementation of vitamin D, B12 and calcium resulted in higher serum levels of vitamins, lower PTH levels and diminished severe vitamin D deficiency and is thus recommended as standard care.