Following a 6 week low lactose diet to treat symptoms of  lactose intolerance, your child should now be well on their way to recovery.  Once symptoms have resolved, reintroducing lactose back into the diet is the next step. Working up from low lactose foods, to medium and then to high lactose containing foods, with daily exposure for about 2-4 weeks does three things:

  • stimulates production of the lactase enzyme in the small intestine where lactose digestion takes place
    • this can only happen in with exposure to lactose
  • helps establish the amount of dietary lactose tolerated
    • if symptoms return, the gut may still be healing
    • maintain a low lactose diet and try reintroduction again in 2-4 weeks
    • cells of the gut turn around every 28 days
  • assists the build up and return of normal lactase production
    • it may take longer than the 2-4 weeks mentioned above to return to a normal diet
    • a threshold may be reached at a certain level of lactose intake
    •  improve tolerance by spreading lactose intake over the day, or eating as part of a mixed dish
Re-establishing tolerance to lactose

Re-establishing tolerance to lactose varies from person-to-person and depends on age and intestinal damage. People with primary lactose intolerance  and permanent reduction in lactase, usually manage 2 – 4g per day and fro teens 4 – 6 g per day.  Return to a normal diet can be expected for most infants and children eg. after rota virus with temporary reduction in lactase. Use the practical guidance below to help reintroduce lactose back into the diet.  Do built up gradually, assessing tolerance (or return of symptoms) at each step. It’s also worth noting the difference between lactose intolerance and cow’s milk allergy because the dietary treatment is different.  Formula fed babies with lactose intolerance, need special attention to milk and solids, so that they get the calcium their bones need for growth and the products used suit their needs. It’s especially important that infants get the right advice because they depend on a high milk diet and are learning strong associations with eating and wellness. This guidance is suitable for children and teens with lactose intolerance, but for infants further information about cow’s milk allergy in infancy may be more relevant.

Lactose content of dairy foods
Very Low Lactose

< 2g per portion

Medium Lactose

2-4g per portion

High Lactose

4-6g per portion

The foods in this group contain very low amounts of lactose and are tolerated by most people with lactose intolerance.  If consuming these foods does not give any symptoms, try medium lactose foods per portion. Continue to introduce lactose containing foods, including foods with medium lactose. If symptoms return, go back to the previous tolerated stage for 2 weeks and try again. In addition to very low and medium lactose content foods, continue to introduce lactose-containing foods, including one portion from the high lactose category.
Cheese 1oz
Most hard cheeses have very small amounts of lactose and are unusually well tolerated. Eg. cheddar, red leicester, caerphilly, stilton, parmasan Cheese spread, cottage cheese, soft cheeses eg. ricotta, marscapone, dolchelate Cheese spread, quark


Yoghurts & fromage-frais 60g 125g Larger portion
Greek yoghurt, Goat’s yogurt, all yoghurts and fromage-frais Yoghurts and fromage-frais, Low fat fruit yoghurts, Organic whole milk yoghurt Natural whole or fruit yoghurt, Low fat natural yoghurt, Diet/low calorie yoghurts
Dairy desserts & creams 2oz 4 – 6oz Larger portion
Half fat cream, Single, Double, Whipping, Clotted cream, UHT Spray Cream, Fresh Cheese Cake 1 scoop ice cream, Frozen cheesecake, Trifle with cream, 1 chocolate mousse 2 scoops ice cream, 10mls Angel Delight, 150g tinned rice pudding, 100mls Custard
Hidden milk
1 x small slice cake, 4 chocolate digestives, 1 chocolate coated biscuit eg. 2 finger kit-kat, 100g egg custard tart 1 milk chocolate bar, 125mls whole milk, 70mls evaporated milk, 1 tblsp skimmed milk powder, 40mls condensed milk