Lactose

The amount of lactose leading to symptoms varies between individuals. Many of those affected tolerate up to 10g of lactose (i.e. one glass of milk) without significant symptoms.

Lactose is present in relatively similar quantities in all mammals’ milk, except some sea mammals.

Consequently, there is no advantage in substituting cow’s milk with other mammal’s milk (e.g. goat’s or sheep’s).

Dairy products contain varying amounts of lactose, depending on processing methods. Besides the evident sources of lactose, the latter is often found in hidden form. Whey, for example, is commonly used in the food industry as a browning or binding agent, or to increase the smoothness and sweetness of food and beverages. Sauces, soups and salad dressing often contain milk powder or products. Lactose is also used as a filler substance in at least 20% of drugs. The lactose content of milk is not greatly affected by heat, fat content (skimmed vs. full fat), but milk consumed with other products (such as chocolate, cereal) may greatly improve tolerability. Yogurt may not cause symptoms, as many of the bacterial strains in yogurt produce lactase, aiding in the breakdown of lactose. Consequently, it is worth comparing the tolerability of different yogurt brands. Hard cheeses and older cheeses generally have low lactose content and are usually well tolerated.

Lactose content may be indicated by the following constituents used in food labels – it is not compulsory to declare lactose content in all countries:

Artificial butter flavor, butter, caramel color or flavoring, casein or caseinate, cheese, cream, dried milk, high protein flour, lactalbumin, lacitol (E966), lactose, lactoferrin, lactoglobulin, milk derivatives or powder or solids, natural flavoring, non-fat milk solids, whey, whey protein and whey solids concentrate.

It should be borne in mind that complete exclusion of all lactose is usually not necessary in lactose intolerance, although this is required for cow’s milk allergy.

Complete exclusion may lead to increased sensitivity towards lactose over time. Continued consumption of small amounts of lactose appear to have beneficial effects on the intestinal flora (microbiome). 

The following foods may contain lactose; food labels should be checked. 

Baked goods (e.g. cake, bread, cookies, crackers, donuts, waffles, pancakes), butter, buttermilk cheese, chocolate, cream, cream soups, curds, custard, deli meats, desserts (e.g. caramel, custard, mixes, mousse, soufflé), egg substitutes, energy drinks and concentrates, frozen yogurt, gravy ghee, half & half, health and muesli bars, hot dogs, ice cream, instant drinks (e.g. ice tea, coffee, Ovaltine), food mixes, kefir, margarine (not all), milk (whole, 2%, 1%, skim, condensed, chocolate, cocoa, evaporated, powdered, lactose reduced), pizza, processed meats, pudding, salad dressing, sausages, seasonings, sherbet, sour cream, whipped toppings and yogurt.

The lactose content of some common food items is listed in the table below.

Many supermarkets now offer lactose-free (i.e. reduced lactose content) dairy products, simplifying adequate intake of calcium, which is especially important in lactose intolerance. This milk often tastes sweeter. The daily calcium requirement is 800mg in children 1 – 5 years, 1200mg in children 6 – 10 years, 1200 – 1500mg in 11 – 24 year olds, 1000mg in 24 – 50 year olds, 1500mg in those over 50 years and 1200 – 1500mg in pregnant and nursing women.

Calcium-rich, non-dairy foods include:

Soymilk (fortified), sardines, salmon (canned with bones), broccoli, orange juice (fortified), chard or okra, spinach, dandelion greens, beans (pinto), turnip greens, tofu, tuna, almonds, rhubarb, oatmeal (fortified) and bread (whole wheat, fortified).

More complete lists of calcium-rich foods can be found on these websites:

At least 20% of patients with lactose intolerance also suffer from fructose intolerance. Celiac’s disease should be excluded.

(the content is listed in %, i.e. g lactose / 100g of product). Extensive lay lactose website.

(enter food you are interested in checking lactose content for, e.g. milk, and click on “full report (all nutrients)”)

Wilder-Smith CH et al.

Fructose and lactose intolerance and malabsorption testing: the relationship with symptoms in functional gastrointestinal disorders.

Aliment Pharmacol Ther 2013