Milk and yogurt: the bone trials came back empty

Dairy builds bones is the oldest line in the aisle, and the randomized evidence does not carry it. A network meta-analysis of 60 trials in 6284 healthy women of mean age 54.2 found no dairy food significantly better than control for bone density. Milk plus yogurt ranked numerically highest on the SUCRA scale, which is a ranking rather than a measured difference. What did shift the number was isolated protein: casein with whey raised total body bone mineral density by 0.04 g/cm2 (95% CI 0.01 to 0.06) and soybean protein by 0.03 g/cm2 (95% CI 0.01 to 0.05), over intervention windows averaging 11.3 months and in women only. Almost everything else that separates the two foods comes from cohorts, which record what people already eat and cannot show cause. The single claim Europe allows for yogurt over milk is narrow and worth knowing: live cultures in yogurt or fermented milk improve lactose digestion of that product in people who have difficulty digesting lactose.

How much is actually in it

• Iodine in plain nonfat yogurt varies more than fourfold between USDA samples, from 33.42 to 146.3 ug per 3.5 oz (100 g), while calcium varies by half. — Yogurt, plain, nonfat, individual sample analyses in USDA Foundation Foods (n = 8 samples) Evidence E source
  Iodine 58.72 ug, range 33.42 to 146.3, spread 192%; cholesterol 3.375 mg, range 2.4 to 4.3, spread 56%; calcium 167.4 mg, range 121.0 to 205.0, spread 50%; magnesium 15.21 mg, range 11.1 to 18.4, spread 48%; ash 1.039 g, range 0.79 to 1.24, spread 43%
• Per 100 g the UK tables give whole milk 4.6 g of lactose and plain Greek yogurt 3.5 g, with the strained yogurt carrying twice the energy. — CoFID 2021 records 12-596 Milk, whole, pasteurized, average and 12-555 Yogurt, Greek style, plain, per 100 g (n = 2 reference records) Evidence E source
  Whole milk 63 calories, fat 3.6 g, saturated 2.29 g, protein 3.4 g, lactose 4.6 g, galactose 0; Greek yogurt 133 calories, fat 10.2 g, protein 5.7 g, lactose 3.5 g, galactose 0.9 g, cholesterol 16.7 mg

What a real portion looks like

• A cup of milk is 244 g in the US survey database and the default yogurt portion is a 170 g container, so a yogurt serving is about seven tenths of a glass of milk. — USDA FNDDS household measures for Milk, whole (food code 11111000) and Yogurt, NFS (food code 11400000) (n = 6 measures for milk, 5 for yogurt) Evidence E source
  Milk 1 cup 244 g, 1 fl oz 30 g, 1 school container 244 g, quantity not specified 244 g; yogurt 1 4 oz container 113 g, 1 6 oz container 170 g, 1 container NFS 170 g, 1 cup 245 g, quantity not specified 170 g

What your body absorbs

• Lactase-deficient adults and controls absorbed calcium equally well from 8.8 oz (250 g) of milk and from 5.2 oz (147 g) of yogurt, each carrying 270 mg of calcium, over 24 hours. — Lactase-deficient adults and lactase-sufficient controls given a 45Ca tracer in milk or in commercial unflavored yogurt Evidence B source
  No difference in area under the blood radioactivity curve between yogurt and milk; lactase-deficient subjects absorbed at least as well as controls
• The EU allows only one health claim that separates yogurt from milk, that live yogurt cultures improve lactose digestion of the product for people who digest lactose poorly. — EU Register on nutrition and health claims, snapshot 2026-09-21, 2330 claims of which 262 authorized (n = 1 authorized claim out of 8 register entries matching yogurt) Evidence E source
  POL-HC-6400 Authorised; the other 7 yogurt entries and the dairy portion claim are non-authorized

What cooking and storage change

• An hour of heating costs milk 70 percent of its vitamin B12 and 40 percent of its thiamin by the USDA retention table, while every mineral stays in full. — USDA Table of Nutrient Retention Factors Release 6, group Dairy and Egg Products, method MILK,HEATED APPROX 1 HOUR, retention code 2153 (n = 16 nutrients in the method row) Evidence E source
  Vitamin B12 30% retained, vitamin C 45%, vitamin B6 55%, thiamin 60%, choline 60%, folate 70%; calcium iron magnesium phosphorus potassium sodium zinc copper riboflavin niacin 100%

What it does to your health

• Observational data link higher yogurt intake with 21 percent lower odds of abdominal obesity in adults, pooled from 9 studies and 47778 people. — Adults in 9 observational studies with 47778 participants, drawn from a review of 28 studies on dairy and abdominal obesity (n = 47778) Evidence C source
  Yogurt OR 0.79 (95% CI 0.70 to 0.89); total dairy OR 0.84 (95% CI 0.76 to 0.93); each 160 g per day of total dairy OR 0.92 (95% CI 0.86 to 0.98)
• Observational data link high milk intake with 23 percent higher odds of Parkinson disease, pooled across 29 cohorts and 1307337 people. — 1307337 participants in 29 prospective cohort studies of food groups and Parkinson disease incidence (n = 1307337) Evidence C source
  Milk OR 1.23 (95% CI 1.07 to 1.43), dairy OR 1.26 (95% CI 1.12 to 1.41), low-fat dairy OR 1.30 (95% CI 1.06 to 1.58) for highest against lowest intake; 13 percent higher risk per 1 cup of milk a day

Safety, limits and interactions

• Observational data link both milk and yogurt with higher odds of acne in people aged 7 to 30, with odds ratios of 1.28 for any milk and 1.36 for yogurt. — 78529 children, adolescents and young adults aged 7 to 30 in 14 observational studies, 23046 acne cases against 55483 controls (n = 78529) Evidence C source
  Any milk OR 1.28 (1.13 to 1.44), low-fat or skim milk OR 1.32 (1.16 to 1.52), yogurt OR 1.36 (1.05 to 1.77), any dairy OR 1.25 (1.15 to 1.36)
• The FDA-approved tetracycline label names calcium among the agents that impair absorption of tetracyclines, alongside aluminum, magnesium, iron and zinc. — Patients taking tetracycline hydrochloride, manufacturer label section on drug interactions, effective 2026-05-22 Evidence E source
  Calcium named among the agents that impair tetracycline absorption, alongside aluminum, magnesium, iron, zinc and sodium bicarbonate

What people believe that the data does not support

• Europe refused the right to say that three portions of dairy a day help children and adolescents keep a healthy body weight. — EU Register on nutrition and health claims, claim POL-HC-6305 for dairy products covering milk, cheese and yogurt Evidence E source
  Status Non-authorized

Who this works differently for

• Observational data link higher yogurt intake with 22 percent lower risk of hip fracture while milk shows no significant association. — Adults in prospective cohort studies of dairy consumption and hip fracture, highest against lowest intake category Evidence C source
  Yogurt RR 0.78 (95% CI 0.68 to 0.90); milk RR 0.86 (95% CI 0.73 to 1.02); cheese RR 0.85 (95% CI 0.66 to 1.08)

What is still unknown

• Across 60 randomized trials in 6284 women no dairy food beat control for bone density, while casein plus whey protein raised total body BMD by 0.04 g per cm2. — 6284 healthy women, mean age 54.2 years, in 60 randomized controlled trials pooled in a network meta-analysis (n = 6284) Evidence A source
  Food level not significant against control, milk plus yogurt ranked numerically highest by SUCRA; casein plus whey protein MD 0.04 g/cm2 (95% CI 0.01 to 0.06), soybean protein MD 0.03 g/cm2 (95% CI 0.01 to 0.05)

The bottom line

Per 100 g the UK tables put whole milk at 63 calories with 4.6 g of lactose and no galactose, and plain Greek yogurt at 133 calories with 3.5 g of lactose and 0.9 g of galactose, the trace that fermentation leaves. Greek yogurt is strained, so read it as one product rather than as yogurt in general. Portions decide more than the per 3.5 oz (100 g) line does. The US survey database defaults milk to a 244 g cup and yogurt to a 170 g container, so a pot is about seven tenths of a glass. Yogurt is also less uniform than the label suggests. Across 8 USDA sample analyses of plain nonfat yogurt, iodine ran from 33.42 to 146.3 ug per 3.5 oz (100 g) and calcium from 121 to 205 mg, a spread that traces to dairy sanitation and feed rather than to the recipe, and Foundation Foods gives no matching row for milk to compare against. For calcium absorption the one trial on record found no difference between them. In a radiocalcium trial, lactase-deficient adults and lactase-sufficient controls absorbed calcium equally well from 8.8 oz (250 g) of milk and from 5.2 oz (147 g) of unflavored yogurt, each carrying 270 mg, judged on blood curves over 24 hours. That paper is from 1985 and has no full text available, so its participant count cannot be recovered. The cohorts then pull the pair apart in both directions, and not one of them can establish cause. Higher yogurt intake was linked to 21 percent lower odds of abdominal obesity (OR 0.79, 95% CI 0.70 to 0.89) across 9 studies and 47778 people, in a review where 22 of 28 studies were cross-sectional. Yogurt was linked to 22 percent lower hip fracture risk (RR 0.78, 95% CI 0.68 to 0.90) while milk missed significance (RR 0.86, 95% CI 0.73 to 1.02), and the authors read the milk result as vitamin D fortification differing between the United States and Scandinavia. High milk intake was linked to 23 percent higher odds of Parkinson disease (OR 1.23, 95% CI 1.07 to 1.43) across 29 cohorts and 1307337 people, with yogurt not significant in the overall analysis. Acne is the one place yogurt looks worse: among 78529 people aged 7 to 30, odds were 1.28 (1.13 to 1.44) for any milk and 1.36 (1.05 to 1.77) for yogurt, and the authors report publication bias in their own pool alongside the widest interval sitting on the yogurt estimate. Europe refused the claim that three portions of dairy a day help children and adolescents keep a healthy body weight, which records evidence falling short at assessment. An hour of heating leaves milk 30 percent of its vitamin B12 and 60 percent of its thiamin by the USDA group factor for dairy, while the minerals survive whole, and that table has no method for yogurt at all. On caution we have one card, the FDA-approved tetracycline label, which names calcium among the agents that impair absorption of the antibiotic. It names antacids and supplements rather than milk, so the timing of a dose around dairy is a question for whoever prescribed or dispensed it. Nothing in this set treats pregnancy or milk allergy as a safety question, and the only age-specific signal is the acne association above, which is observational and cannot show cause.

Sources

1. mkyg-daily-r1-10 · reference dataset
   Yogurt, plain, nonfat | Iodine, I 58.72 UG range 33.42-146.3 median 49.97 n=8 spread 192% | Cholesterol 3.375 MG range 2.4-4.3 n=8 spread 56% | Calcium, Ca 167.4 MG range 121.0-205.0 n=8 spread 50% | Magnesium, Mg 15.21 MG range 11.1-18.4 n=8 spread 48% | Ash 1.039 G range 0.79-1.24 n=8 spread 43%
   USDA FoodData Central, Foundation Foods, release 2026-04-30 · checked 2026-09-25
2. mkyg-daily-r1-11 · reference dataset
   CoFID 12-596 Milk, whole, pasteurised, average: Energy 63 kcal, Fat 3.6 g, Satd FA /100g fd 2.29 g, Protein 3.4 g, Lactose 4.6 g, Galactose 0.0 g, Cholesterol 12.0 mg | CoFID 12-555 Yogurt, Greek style, plain: Energy 133 kcal, Fat 10.2 g, Protein 5.7 g, Lactose 3.5 g, Galactose 0.9 g, Cholesterol 16.7 mg, Carbohydrate 4.8 g
   CoFID 2021, Public Health England, records 12-596 and 12-555 · checked 2026-09-25
3. mkyg-daily-r1-12 · reference dataset
   Milk, whole, FNDDS 11111000: 1 cup 244 g | 1 fl oz 30 g | 1 individual school container 244 g | Quantity not specified 244 g || Yogurt, NFS, FNDDS 11400000: 1 4 oz container 113 g | 1 6 oz container 170 g | 1 container, NFS 170 g | 1 cup 245 g | Quantity not specified 170 g
   USDA FNDDS, Milk whole code 11111000 and Yogurt NFS code 11400000 · checked 2026-09-25
4. mkyg-daily-r1-02 · randomized controlled trial
   Subjects ingested 270 mg of Ca plus 45Ca in 250 g of milk or 147 g of commercial, unflavored yogurt, and blood radioactivity was assessed at intervals over 24 h. Based on the areas under the blood radioactivity curves, lactase-deficient subjects and controls absorbed calcium equally well from yogurt and milk.
   Am J Clin Nutr, 1985 · checked 2026-09-25
5. mkyg-daily-r1-03 · EU claims register entry
   POL-HC-6400 Live yoghurt cultures Live cultures in yoghurt or fermented milk improve lactose digestion of the product in individuals who have difficulty digesting lactose Authorised
   EU Register on nutrition and health claims, claim POL-HC-6400, snapshot 2026-09-21 · checked 2026-09-25
6. mkyg-daily-r1-13 · nutrient retention factor dataset
   USDA-RETN-R6:2153 | Dairy and Egg Products | MILK,HEATED APPROX 1 HOUR | vitamin_b12_ug 30% retained | vitamin_c_mg 45% | vitamin_b6_mg 55% | thiamin_mg 60% | choline_mg 60% | folate_total_ug 70% | calcium_mg 100% | iron_mg 100% | magnesium_mg 100% | phosphorus_mg 100% | potassium_mg 100% | sodium_mg 100% | zinc_mg 100% | copper_mg 100% | riboflavin_mg 100% | niacin_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Code 2153 · checked 2026-09-25
7. mkyg-daily-r1-05 · meta-analysis of observational studies
   Pooling effect sizes from 9 eligible studies with 47 778 participants showed that higher amounts of yogurt consumption was related to a 21% reduction in abdominal obesity (OR = 0.79; 95% CI, 0.70-0.89).
   Nutr Rev, 2026 · checked 2026-09-25
8. mkyg-daily-r1-06 · meta-analysis of prospective cohorts
   High consumption of dairy, low-fat dairy, and milk demonstrated 26% (odd ratio [OR], 1.26; 95% CI, 1.12-1.41), 30% (OR, 1.30; 95% CI, 1.06-1.58), and 23% (OR, 1.23; 95% CI, 1.07-1.43) increased PD risk compared with the lowest intake categories, respectively.
   Nutr Rev, 2026 · checked 2026-09-25
9. mkyg-daily-r1-08 · meta-analysis of observational studies
   ORs for acne were 1.25 (95% CI: 1.15⁻1.36; p = 6.13 × 10-8) for any dairy, 1.22 (1.08⁻1.38; p = 1.62 × 10-3) for full-fat dairy, 1.28 (1.13⁻1.44; p = 8.23 × 10-5) for any milk, 1.22 (1.06⁻1.41; p = 6.66 × 10-3) for whole milk, 1.32 (1.16⁻1.52; p = 4.33 × 10-5) for low-fat/skim milk, 1.22 (1.00⁻1.50; p = 5.21 × 10-2) for cheese, and 1.36 (1.05⁻1.77; p = 2.21 × 10-2) for yogurt compared to no intake.
   Nutrients, 2018 · checked 2026-09-25
10. mkyg-daily-r1-09 · FDA drug label section
    Absorption of tetracyclines is impaired by antacids containing aluminum, calcium or magnesium and preparations containing iron, zinc, or sodium bicarbonate.
    Tetracycline Hydrochloride, FDA-approved label, drug interactions section, effective 2026-05-22 · checked 2026-09-25
11. mkyg-daily-r1-04 · EU claims register entry
    POL-HC-6305 Dairy products (milk, cheese and yoghurt) Three portions of dairy food everyday, as part of a balanced diet, may help promote a healthy body weight during childhood and adolescence. -/- Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6305, snapshot 2026-09-21 · checked 2026-09-25
12. mkyg-daily-r1-07 · meta-analysis of prospective cohorts
    In the meta-analysis of the highest versus lowest category of consumption, higher consumption of yogurt (RR 0.78, 95% CI 0.68, 0.90), but not milk (RR 0.86, 95% CI 0.73, 1.02) or cheese (RR 0.85, 95% CI 0.66, 1.08), was associated with a lower risk of hip fracture.
    Osteoporos Int, 2020 · checked 2026-09-25
13. mkyg-daily-r1-01 · network meta-analysis
    At the food level, no dairy or soy interventions significantly improved outcomes versus control, although milk + yogurt ranked numerically highest based on SUCRA values. At the bioactive-component level, the combination of casein + whey protein (MD 0.04 g/cm2, 95% CI 0.01-0.06) and soybean protein (MD: 0.03 g/cm2, 95% CI: 0.01-0.05) significantly increased TB BMD.
    Nutrients, 2025 · checked 2026-09-25