The Mystery of the Disappearing Lactose

This is a guest blog post by Richard Perlmutter, MS

The only sugar in milk is lactose, a sugar that some people have trouble digesting. All of the lactose is in the fat free portion, not in the milk fat. At a higher level of milk fat, a dairy product will have a lower level of lactose.

Fat free milk has about 5 percent  (5g of 100g) sugars, all as lactose.

Half and half may be regarded as a combination of about 90 percent fat free milk and 10 percent milk fat. It has about 4.5 percent sugars as lactose, 90 percent as much as in fat free milk.

Light cream is a combination of about 80 percent fat free milk and 20 percent milk fat. So it has about 4 percent sugars as lactose. It has 80 percent as much as in fat free milk.

Heavy cream is a combination of about 60 percent fat free milk and 40 percent milk fat. So it has about 3 percent sugars as lactose. It has 60 percent as much as in fat free milk.

Now look at some nutrition facts panel information for the four:

  • A serving (8 fl oz) of fat free milk has 12g sugars
  • A serving (2 Tbsp-1 fl oz) of half and half has 1g sugars
  • A serving (1Tbsp) of light cream has less than 1g sugars
  • A serving  (1 Tbsp) of heavy cream has 0g sugars

So where did all the lactose go?

The main reason the amount dwindles to what looks like nothing (0g), is that the serving sizes become smaller and smaller. The little that is in one tablespoon of heavy cream (about 0.45g) gets swallowed up by the FDA rule which requires that less than 0.5g per serving be declared as 0g per serving.

The point of this discussion is to show that very small serving sizes also make nutrient values look very small, even down to zero. Sometimes, as with the lactose content of heavy cream, this can give a false sense of assurance to those who are sensitive to a nutrient.
Richard Perlmutter is the owner of Abington Nutrition Services LLC which prepares nutrition labeling for products manufactured by food and beverage companies. He also takes an interest in seeing that government nutrition policy is in line with nutritional science.

(References to this article are available on request from the author.)

  • The Candid RD

    Right, but you wouldn’t necessarily use more than 1Tbsp. heavy cream. I see your point though…and I’m NOT a fan of the .5 grams or less rule!

  • Sierra

    This was very confusing

  • Jill

    I like the aspect of Fooducate that it is more of a conversational than a full-on science and nutrition study. While I like research studies full of cold calculated language, there is a time and place for everything. For that reason, I am not into this guest contributor.

  • Sarah

    I like the science aspect of Fooducate. Keep it up!