What is lactose intolerance?
Lactose intolerance occurs when a baby does not have enough lactase. Lactase is an enzyme needed to digest lactose, one of the carbohydrates, or sugars, present in cow's milk and cow's milk–based formulas.

Lactose intolerance often occurs during diarrhea, which can damage digestive enzymes. This type of lactose intolerance is called secondary lactase deficiency, and is usually a temporary condition.

An extremely small percentage of infants may have congenital lactase deficiency, which means that they were born unable to produce lactase. Congenital lactase deficiency is usually permanent.

What are the symptoms of lactose intolerance?
The main symptoms of lactose intolerance are watery diarrhea, abdominal pain and bloating, and gas. Symptoms usually occur within 30 to 60 minutes of drinking cow's milk or a cow's milk–based formula.

When lactose intolerance is suspected, a diagnosis cannot be based solely on symptoms, because diarrhea, abdominal pain, and vomiting occur also with other disorders. Your health care professional can perform medical tests to confirm whether your baby is lactose intolerant.

Is lactose intolerance serious?
It usually is not serious, but it can take longer to recover from diarrhea if lactose intolerance is not treated quickly and appropriately. Further, if diarrhea continues for longer than 2 weeks, your baby's nutrition can be compromised. That's why you should always consult your health care professional when your baby experiences diarrhea. Please see also Diarrhea.

How is lactose intolerance treated?
Lactose intolerance is treated by reducing lactose or eliminating it from the diet. Lactose is present in dairy products and standard cow's milk–based infant formulas.

Clinical studies have shown that lactose-free (LF) formulas help hasten recovery from diarrhea and improve the nutritional status of bottle-fed babies.

For years, soy formulas have served as a nutritious alternative when a lactose-free diet is necessary. See Soy Formulas for more information.

Recently, lactose-free milk-based formulas have been developed. These formulas are rich sources of protein, calcium, and energy, but contain very little or no lactose. These LF formulas tend to be well accepted by babies because they taste similar to standard formulas.

What should I look for in a lactose-free milk-based formula?

• Has a whey-dominant protein like that of breast milk (60% lactalbumin) that is easy to digest.
  
  
• Is fortified with nucleotides, which have been shown to help prevent the recurrence of diarrhea.
  
  
• Tastes similar to standard infant formula, which makes it more acceptable to baby.
  
  
• Provides complete and balanced nutrition, including beta-carotene/mixed carotenoids.

Wyeth's lactose-free (LF) formula meets all of these requirements.

How long do babies need to be fed lactose-free formulas?
Generally, lactose should be eliminated for 2 to 4 weeks to treat a secondary lactase deficiency. After this time, lactose-containing feedings can be reintroduced gradually. However, in some instances, lactase activity may not be completely back to normal for 2 to 4 months.

Babies with congenital lactase deficiency may need to continue a lactose-free diet indefinitely.

Your health care professional can best advise how long your baby may need to be fed an LF formula.