Lactose — The Infant Formula Atlas

By María López Botín · Mother of 2, researching infant formula and infant nutrition since 2018

Lactose is the sugar naturally present in mammalian milk. It is the predominant carbohydrate in human breast milk, accounting for roughly 40% of the calories a breastfed baby gets, and the EU requires it to be the main carbohydrate in infant formula as well. The US does not require this, which is the single biggest reason European infant formulas read differently from American ones at the ingredient level.

What lactose is

Lactose is a disaccharide, two simple sugars bonded together, composed of one molecule of glucose and one of galactose. In the infant gut, the enzyme lactase breaks that bond, releasing both sugars for absorption. Lactose is not added to formula as a flavor or sweetener; it is added because it is the sugar the human infant digestive tract evolved to process, and because the fermentation products of lactose in the lower gut feed the specific bacteria (Bifidobacterium) that dominate a healthy breastfed infant's microbiome.

Breast milk is about 7 grams of lactose per 100 millilitres. EU infant formula compliant with Regulation 2016/127 sits in the same range: HiPP Dutch Stage 1, for example, provides 7.0 g total carbohydrate per 100 ml with lactose as the primary source.

Why the EU requires lactose as the predominant carbohydrate

EU Commission Delegated Regulation 2016/127, Article 5.1, is the rule. It states that lactose, or, in limited cases, lactose combined with whey-derived carbohydrate, must be the predominant carbohydrate in infant formula made from cow or goat milk protein. The regulator's reasoning, drawn from European Food Safety Authority scientific opinions, is that lactose's behavior in the infant gut is the best-studied and most closely matches the breastfeeding baseline. Substituting alternative carbohydrates is permitted only when a specific medical indication justifies it (e.g., lactose intolerance, which is extremely rare in infants; or hypoallergenic formulas where lactose is removed for other reasons).

The predominant-lactose rule is why European infant formulas list "lactose" as one of the first three ingredients, and why corn syrup solids, maltodextrin, or glucose syrup do not appear in compliant EU Stage 1 formulas unless the formula is marked as a special-medical variant.

How US regulation differs

FDA 21 CFR Part 107 regulates US infant formula but does not specify the required carbohydrate source. It sets minimum nutrient levels and safety requirements, but the choice of carbohydrate is left to the manufacturer. This is why several widely-sold US formulas: Enfamil Gentlease, Similac Total Comfort, Similac Sensitive among others, use corn syrup solids as the primary carbohydrate, which would fail EU compliance. Bobbie is the most prominent US brand that voluntarily uses lactose as the predominant carbohydrate, matching the EU approach without being required to.

The practical consequence for parents: when comparing a US formula against a European one, the carbohydrate source is often the starkest single difference, and it is also the difference most likely to matter for a baby's short-term comfort (gas, stool consistency, satiety) and long-term microbiome composition.

When formulas use lactose alternatives (and why)

Legitimate reasons to use a non-lactose primary carbohydrate:

Hypoallergenic (hydrolyzed) formulas, the hydrolysis process typically uses glucose syrup or maltodextrin. Examples: Nutramigen, Alimentum, HiPP HA.
Lactose intolerance / galactosemia, rare in infants; requires a medically supervised specialty formula such as Similac Soy Isomil, Enfamil ProSobee, or a lactose-free cow milk variant.
Anti-reflux formulas, some variants thicken with starch or rice flour that reduces lactose percentage.

Reasons that are not medically justified but do occur in the US market:

Cost engineering, corn syrup solids are cheaper than lactose.
Palatability marketing, sweeter taste.
Historical formulation, brands that switched in the 1990s and never switched back.

The Infant Formula Atlas flags formulas that use corn syrup solids or maltodextrin as primary carbs under our red-flag filter; see formulas without corn syrup for the full cross-brand list (Phase 1).

Who should consider a low-lactose or lactose-free formula

True infant lactose intolerance is rare and almost always secondary, it follows a gut-lining injury from gastroenteritis, and resolves as the gut heals. Congenital lactase deficiency is extremely rare and diagnosed by a paediatrician, not inferred from gassiness. Most "my baby is lactose intolerant" conclusions that parents reach independently are actually reactions to something else, cow-milk protein sensitivity, overfeeding, or normal infant gas.

If your pediatrician has diagnosed lactose intolerance or CMPA, the specialty formulas above are the evidence-based path. If you're troubleshooting a gassy or unsettled baby without a diagnosis, do not switch to a low-lactose formula as a first move, it is more likely to make things worse than better in the long term. Talk to your pediatrician before changing.

Formulas using lactose as the primary carbohydrate

Phase 1 will auto-generate this cross-reference from the Atlas YAML corpus. The list below will grow as we verify more SKUs:

HiPP Dutch Stage 1
Holle Stage 1 (cow), pending verification
Kendamil Classic Stage 1, pending verification
Lebenswert Stage 1, pending verification
Jovie Stage 1 (goat), pending verification
Bobbie Original, pending verification (US brand using lactose voluntarily)

Frequently asked questions

Is lactose the same sugar that's in breast milk?

Yes — lactose is the predominant carbohydrate in human breast milk, accounting for roughly 40% of total calories. Breast milk contains about 7g of lactose per 100ml. EU-compliant infant formulas (HiPP, Holle, Kendamil, Lebenswert) match this profile by regulation. Lactose is the carbohydrate the infant gut evolved to digest, and its fermentation by gut bacteria supports the Bifidobacterium-dominant microbiome characteristic of healthy breastfed infants.

Why do some US formulas use corn syrup solids instead of lactose?

FDA 21 CFR 107 does not require lactose as the primary carbohydrate — it sets minimum nutrient adequacy but leaves the carbohydrate source to manufacturer choice. Corn syrup solids are cheaper than lactose, can deliver the carbohydrate calorie load required, and produce a sweeter taste profile. EU regulation explicitly prohibits this substitution unless medically justified. The practical implication: parents comparing US and EU formulas often see this as the single starkest ingredient difference.

Is lactose intolerance common in infants?

True congenital lactase deficiency is extremely rare — diagnosed by a pediatrician, not inferred from fussiness. Secondary (transient) lactose intolerance can follow gastroenteritis or gut-lining injury and resolves as the gut heals. Most parental conclusions of 'my baby is lactose intolerant' are actually reactions to something else: cow milk protein sensitivity, overfeeding, or normal infant gas. Switching to a low-lactose formula without diagnosis is more likely to harm the microbiome than help short-term symptoms.

What's the difference between lactose and reduced-lactose formulas?

Reduced-lactose formulas (Similac Sensitive, Enfamil Gentlease 'Sensitive Tummies' line) replace 70-80% of lactose with corn syrup solids or maltodextrin. They're marketed for fussiness/gas but do not address actual CMPA. AAP and most pediatric specialists do not recommend reduced-lactose formula for typical infant gas — it removes a beneficial carbohydrate without providing clinical benefit for the vast majority of babies experiencing normal digestive variability.

Does HMO replace some of the lactose in modern formulas?

No. 2'-FL HMO and other Human Milk Oligosaccharides are added at very low concentrations (typically 1.0-1.5g per liter, similar to breast milk levels) and serve as prebiotic substrates for gut bacteria, not as primary calorie sources. Lactose remains the predominant carbohydrate in HMO-fortified formulas; HMO is added on top of the lactose base. Formulas like HiPP Dutch with HMO + lactose mirror the breast milk pattern of both nutrients working together.

Can I tell from the label whether a formula is lactose-primary?

Yes — ingredients are listed by weight, so the carbohydrate appearing first or second on the ingredient list is the predominant one. EU formulas list 'lactose' or 'demineralized whey' (which is lactose-rich) prominently. US formulas using corn syrup solids list 'corn syrup solids,' 'maltodextrin,' or 'glucose syrup solids' as the primary carb. Bobbie Original is the most prominent US brand voluntarily using lactose; Earth's Best, ByHeart, and Similac 360 Total Care also use lactose as primary carb.

Primary sources

EU Commission Delegated Regulation 2016/127: Article 5.1 on carbohydrate composition. eur-lex.europa.eu
FDA 21 CFR Part 107. US infant formula regulation. ecfr.gov
Belew CL, et al. Lactose in human milk: natural history and feeding infants with lactose intolerance. Nutrients, 2023. pubmed.ncbi.nlm.nih.gov/37242246
DiMaggio DM, et al. Comparison of imported European and US infant formulas. JAMA Pediatrics, 2019. pubmed.ncbi.nlm.nih.gov/31107795

Lactose-primary brands and comparisons, HiPP brand hub, Holle brand hub, Kendamil brand hub, HiPP vs Bobbie comparison (both lactose-primary, different composition philosophies)
Infant lactose intolerance, real vs perceived
How to read a formula label

This site provides research and comparisons, not medical advice. Consult your pediatrician before changing your baby's formula.

Formulas containing lactose

Primary sources