Lactase deficiency

Treatment is indicated only when lactase deficiency manifests as a clinical syndrome of lactose intolerance.[1] [2] [3] [56]

Adherence to a lactose-free diet is difficult for those with severe lactose intolerance, and dietary changes may lead to deficiencies in calcium and other nutrients. Patients should be encouraged to acquaint themselves with the lactose content of common foods.University of Virginia Digestive Health Center: lactose content of common dairy foods Dietitian consultation should be sought at diagnosis, then yearly; and also if persistent symptoms suggest a source of hidden lactose. Dietitians will not only stress long-term use of low lactose (or lactose-free) dairy products, but will also give advice on diets rich in calcium and vitamin D.[57] Although there is a lack of evidence supporting calcium and vitamin D replacement for patients with lactose intolerance, most clinicians endorse this approach in practice.[58]

Advice regarding substitution of alternative nutrient sources to maintain good energy and protein intake is also very important.

Severe disease associated with calcium and vitamin D deficiency, and patients with osteopenia on DEXA scans, require adjunctive calcium and vitamin D supplementation.

Treatment consists of limitation of lactose-containing foods, use of lactase-treated dairy products, oral lactase supplementation, or elimination of dairy and nondairy (hidden) lactose.[1] [2] [3] [56] [59] Examples of sources of nondairy lactose include baked goods, processed food, "slimming" products, nondairy toppings or creamers, and some medications.[60]

The threshold for lactose varies between people. Most patients can tolerate a glass of milk (240 mL = 11 g lactose) a day, whereas others develop symptoms with just 2 to 3 g lactose from a chocolate bar.[28] [61] It may help to divide daily milk intake into several portions and take it with other foods. Several studies have shown that individuals with lactose intolerance can take 1 to 2 cups of milk or equivalent amounts of cream, ice cream, or yogurt a day without significant symptoms.[10] [25] [28] [62] [63] [64]

Once the diagnosis has been established, patients should experiment carefully with a variety of foods to discover their lactose threshold.

In particular, patients with severe lactose intolerance should actively look for and avoid lactose-containing dairy and nondairy products. Patients (or their parents) must be instructed to read the ingredients labels of commercially prepared foods, drinks, and drugs (lactose is widely used as a bulking agent or filler in pharmaceuticals).[1] [63] [66] Many processed and ready-to-eat foods, and some weight-reducing diet foods, are high in lactose but lack labeling. Some patients with coexistent irritable bowel syndrome that is responsive to a diet that is low in fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) may feel gastrointestinal symptomatic improvement with reduction of both lactose and FODMAPs.[58] [67]

Supplements and adjunctive treatments may be necessary for patients who reduce their lactose intake significantly.

Treatment of secondary lactase deficiency and lactose malabsorption attributable to an underlying condition involves treatment of underlying causes (e.g., small bowel injury, acute gastroenteritis, small bowel bacterial overgrowth, celiac disease, cancer chemotherapy, or other causes of injury to the small intestinal mucosa). Generally, these patients do not require dietary lactose restriction, although some patients with significant symptoms may need to temporarily restrict their intake of dairy products for symptomatic improvement. These patients may also require lactase, calcium, and vitamin D supplements, as well as nutritionist consultation. Lactose-containing products can often be consumed normally after resolution of the primary problem.[2] [16] [56] Probiotics containing Bifidobacterium longum and Enterococcus faecium may be useful in correcting lactase deficiency in patients with post-infectious irritable bowel syndrome, but this still needs to be validated in larger studies.[72]

It is recommended that all premature infants are breast-fed and/or given lactose-containing formulas. Those who develop symptoms of lactose intolerance may be fed with lactase supplements for a period of a few weeks to 2 months. Lactase supplements may be taken with human milk or with formulas containing lactose, as there is no evidence that either human milk or formulas containing lactose have either short- or long-term deleterious effects on preterm infants.[73] Avoidance of lactose-containing formulas and of human milk is only recommended in patients with severe symptoms of lactose intolerance; if necessary, it is only recommended for a very short period.

There is limited evidence regarding the beneficial effects of lactose reduction and lactase supplementation.[2]

Developmental disease rapidly improves with maturation of the intestinal mucosa. These patients do not need calcium, vitamin D supplements, and nutritionist consultation as, if they are symptomatic, symptoms only last for a few weeks. Lactose can be reintroduced after a few weeks to 2 months depending on the degree of prematurity of the infant.

Without early recognition and prompt treatment, congenital lactase deficiency is potentially life threatening. Initial management of diarrhea includes intravenous rehydration and replacement of electrolytes. The only treatment is complete avoidance of lactose from birth. Treatment is lifelong and consists of simple removal of lactose from the diet and substitution with a commercial lactose-free formula.

These patients require nutritionist consultation and are likely to require calcium and vitamin D supplements.