Lactose intolerance affects an estimated 5% of UK adults of Northern European descent and a substantially higher proportion of adults of Asian, African and Mediterranean origin. The condition is distinct from cow's milk allergy, has a clear symptom pattern, and is usually well managed with dietary adjustment supported by lactase enzyme supplements where useful. Community pharmacy is well placed to confirm the symptom pattern, advise on supplement choice and identify the often-overlooked source of breakthrough symptoms: lactose excipient in oral medicines.

This guide summarises the practical management points, drawing on the NICE Clinical Knowledge Summary on lactose intolerance, the BNF excipients appendix, and the British Dietetic Association food fact sheets.

Lactose intolerance versus cow's milk allergy

The two conditions are commonly confused; the management is very different.

Patients describing facial swelling, urticaria, breathing difficulty, vomiting or eczema after dairy should be referred to a GP for allergy assessment, not directed to a lactase supplement.

Diagnosis

The NICE CKS identifies three diagnostic options:

• A short empirical lactose-exclusion trial (2–4 weeks), followed by reintroduction
• A hydrogen breath test (gold standard but not always locally available)
• Lactose tolerance test (less commonly used)

A patient with classic symptoms relieved by dairy avoidance and reproduced by reintroduction does not always need formal testing.

Lactase enzyme supplements

Lactase enzyme drops, capsules and tablets allow patients to digest some dairy without symptoms.

Counselling points:

• Take the supplement with the first bite or sip of dairy, not before
• Effect is dose-related; one capsule typically covers a glass of milk equivalent
• Heat does not destroy the enzyme appreciably
• Lactose-free milks (Lactofree, Arla Lactofree) and plant-based alternatives are often more practical for daily use

Hidden lactose in oral medicines

Lactose is one of the most widely used tablet excipients. The BNF maintains an excipients list highlighting medicines that contain lactose, gluten, propylene glycol and other potential triggers. The amount per tablet is usually small — between 50 and 200 mg — but for patients on multiple daily doses or those with very low lactase activity, breakthrough symptoms can occur.

Common categories where lactose is frequently present:

• Generic oral contraceptives
• Many beta-blockers and ACE inhibitors
• Statins (some brands; check the SmPC)
• Levothyroxine generics
• Several SSRIs
• Iron salts
• Many oral antibiotics (clarithromycin, lincosamides)

The patient information leaflet (PIL) and the manufacturer's Summary of Product Characteristics (SmPC) both list excipients explicitly. Where lactose intolerance is causing symptoms despite dietary control, switching to a lactose-free brand or a film-coated tablet (often lactose-free) usually resolves the issue. Pharmacists can request the SmPC from the dispensary computer, the BNF or electronic Medicines Compendium.

Breakthrough sources of lactose

Patients often forget the smaller everyday sources:

• Bread (some brands use milk powder)
• Processed meats (sausages, deli slices)
• Salad dressings and creamy sauces
• Chocolate (especially milk chocolate)
• Margarines containing whey
• Protein bars and shakes (often whey-based)
• Crisps with cheese flavouring
• Some flavoured medicines (paediatric oral liquids)

For paediatric patients, the choice of medicine flavouring matters: some manufacturers use lactose carriers in oral powders and granules. The pharmacist's role at point of dispensing is to ask, particularly when changing brand.

Calcium and bone health

Patients on a low-dairy diet need to replace calcium from non-dairy sources to maintain a daily intake of 700 mg (adults) or higher (postmenopausal women, adolescents).

Practical replacement options:

• Calcium-fortified plant-based milks (most provide 120 mg per 100 ml)
• Tinned sardines and pilchards (with bones)
• Tofu (calcium-set)
• Leafy greens (kale, broccoli, cabbage)
• Sesame seeds, tahini
• Almonds
• Calcium-fortified breakfast cereals
• OTC calcium and vitamin D supplements where dietary intake is inadequate

Vitamin D supplementation (10 micrograms / 400 IU daily, October to March) remains an NHS recommendation for the general adult population and year-round for at-risk groups.

Children

Most apparent lactose intolerance in infants is secondary to a temporary gut episode (gastroenteritis, antibiotics, cow's milk protein allergy). Primary lactase deficiency rarely presents under five years of age. Infants showing chronic symptoms should be referred to a GP for paediatric assessment rather than offered an enzyme supplement directly.

When to refer

• Suspected cow's milk protein allergy
• Persistent symptoms despite dietary control and lactase supplementation
• Weight loss, growth failure in children, anaemia, recurrent bowel symptoms (rule out coeliac disease, IBD, IBS, exocrine pancreatic insufficiency)
• New onset lactose intolerance in middle age or later — secondary causes more likely

A pharmacy consultation structure

The first point of pharmacy contact for lactose-related symptoms should cover:

1. Symptom timing and dose-relationship (intolerance is dose-related; allergy is not)
2. Severity and any features suggesting allergy
3. Existing dietary management
4. Calcium replacement adequacy
5. Review of regular medicines for lactose excipient
6. Signposting to GP if any red flag

PharmSee's pharmacy directory helps patients find a community pharmacy for a face-to-face consultation; the pharmacist career hub covers the wider clinical role of the community pharmacist in self-care nutrition advice. The PharmSee jobs board lists current pharmacist and pharmacy technician vacancies across the UK.

Sources

• NICE Clinical Knowledge Summary: Lactose intolerance
• BNF — Excipients
• British Dietetic Association — Food Fact Sheet: Lactose
• NHS — Lactose intolerance
• Royal College of Paediatrics and Child Health — Cow's milk allergy guidance