Parmesan cheese: small trials, big doses

Most of the strong evidence on this page was not about Parmesan. The two meta-analyses pooled trials of hard cheese in general, and they compared it with butter. Eating about 145 g of hard cheese a day in place of butter lowered LDL cholesterol by 6.5 percent, and HDL cholesterol fell by 3.9 percent along with it. That is a swap between two fats. It tells you nothing about adding cheese on top of what you already eat, and the amount is far beyond a grating over pasta. In a six-week trial, 49 adults who replaced part of their usual fat with cheese saw no rise in LDL compared with their habitual diet. The studies that used Parmesan itself were tiny. In 8 people with type 2 diabetes, 50 g of Parmesan and a boiled egg eaten half an hour before a glucose drink cut the peak in blood sugar by 49 percent compared with drinking water beforehand. A second trial with the same preload in 16 people found amino acids in the blood 24 percent higher. Both were single tests on a single morning. Until someone repeats them in more people and over weeks, they are a lead worth watching and too thin to plan your meals around.

The numbers, per 100 g

How much is actually in it

• US rules define Parmesan as cheese with at most 32% moisture that is cured for at least 10 months. — Cheese sold as Parmesan or reggiano in the United States Evidence E source
  Moisture 32% or less, milkfat in solids 32% or more, curing 10 months or more

What your body absorbs

• In 16 people with type 2 diabetes, a 50 g Parmesan and egg preload raised plasma amino acids by 24%, and this rise tracked better beta cell function. — 16 type 2 diabetes patients, two 75 g OGTTs preceded by water or the preload (n = 16) Evidence B source
  Plasma amino acids +24% (p < 0.0001), correlation with beta cell function r = 0.58

What it does to your health

• Across 5 randomised trials, eating about 145 g/day of hard cheese instead of butter lowered LDL cholesterol by 6.5% and HDL cholesterol by 3.9%. — Healthy adults in 5 RCTs comparing hard cheese with butter of similar P/S ratio (n = 5 RCTs) Evidence A source
  LDL-C -0.22 mmol/l (95% CI -0.29 to -0.14), HDL-C -0.05 mmol/l (95% CI -0.09 to -0.02), no effect on triglycerides
• Pooled across 7 trials, 135 g/day of hard or semi-hard cheese for at least 14 days lowered LDL cholesterol by 0.19 mmol/L compared with butter of equal energy. — Adults in 7 RCTs, at least 14 days, mean 135 g cheese per day versus about 52 g/day butter (n = 7 RCTs) Evidence A source
  LDL-C WMD -0.19 mmol/L (95% CI -0.27 to -0.12), total cholesterol -0.24 mmol/L, HDL-C -0.04 mmol/L
• In a crossover trial of 49 adults, 6 weeks of hard cheese supplying 13% of energy gave lower LDL cholesterol than butter with the same fat content. — 49 men and women, two 6-week crossover periods after a 14-day run-in (n = 49) Evidence B source
  Lower total, LDL and HDL cholesterol with cheese than butter, no difference in fecal fat excretion
• In 30 treated hypertensive adults, 30 g/day of Grana Padano for 2 months lowered 24-hour systolic blood pressure by 3.5 mmHg versus placebo. — 30 mild to moderate hypertensive patients not at target despite 3 months of stable treatment, crossover, 2 months per arm (n = 30) Evidence B source
  24-h ambulatory BP -3.5 mmHg systolic, -2.4 mmHg diastolic versus a placebo matched to the cheese for fats and salts
• In 9 healthy adults eating 25 g of Grana Padano daily for 5 days, oral pH shifted toward basic for a few hours after eating. — 9 orally healthy adults, 25 g Grana Padano per day for 5 days (n = 9) Evidence C source
  Oral pH shift toward basic for a few hours, lower S. mutans/S. sanguinis ratio at last time point

Safety, limits and interactions

• In children allergic to egg, lysozyme-treated Grana Padano aged 12 months caused reactions in 5 of 21, versus 1 of 21 after 24 months of ripening. — 21 lysozyme-sensitised children with egg allergy, oral provocation with Grana Padano aged 12 or 24 months (n = 21) Evidence B source
  Adverse reactions 5/21 at 12 months of ripening versus 1/21 at 24 months

What people believe that the data does not support

• In a report on 3 infants, the authors state, without measuring it in this paper, that Parmigiano Reggiano cheese is free of lactose and rich in easily absorbed peptides. — 3 nursing infants with intestinal disorders, case series (n = 3) Evidence D source
  Authors report symptom improvement, no controlled comparison

Who this works differently for

• In 8 adults with type 2 diabetes, 50 g of Parmesan plus one boiled egg eaten 30 minutes before a glucose load cut peak blood glucose by 49% compared with a water preload. — 8 well-controlled type 2 diabetes patients aged 40-70, preload 30 min before a 300-min OGTT (n = 8) Evidence B source
  Peak glucose -49% versus a water preload, glucose iAUC -28%, insulin secretion +22%, GLP-1 iAUC +463%

What is still unknown

• Two Brazilian food composition tables disagreed by 48% on the cholesterol content of Parmesan, 100.7 versus 68 mg per 100 g. — 41 foods analysed in Brazil and compared with two reference tables (n = 41 foods) Evidence C source
  Parmesan cholesterol 100.7 mg/100 g (Unicamp) vs 68 mg/100 g (UNIFESP)

The bottom line

If you like Parmesan, nothing here says stop, and nothing here says eat more of it for your health. Two of the trials used Grana Padano, which is a different cheese, so we name it as such. In 30 people whose blood pressure stayed high after three months of treatment, 30 g of Grana Padano a day for two months lowered 24-hour systolic pressure by 3.5 mmHg against a placebo. That is one small trial on top of their medicines. It does not replace them. Parmesan is a salty cheese, and this trial does not help with that. Its placebo was made with the same salt as the cheese, and the report we read gives no sodium figure. By our USDA numbers, hard Parmesan has 1175 mg of sodium per 100 g, so 30 g carries about 353 mg. Another, in 9 adults eating 25 g a day, found the mouth turned less acidic for a few hours. It measured pH and mouth bacteria over five days and says nothing yet about cavities. You will often read that aged Parmesan contains no lactose. The source we found for that is a report on 3 babies with gut problems and no comparison group. Its authors state that the cheese has no lactose, but they did not measure it, and a report like that cannot tell you whether you personally will tolerate the cheese. It is also no reason to give Parmesan to a baby, and that question belongs with your paediatrician. If your child is allergic to egg, one finding matters. Children sensitised to lysozyme were given Grana Padano that contained it, and 5 of 21 reacted to the 12-month cheese, with symptoms from itching and vomiting to asthma and angioedema. After the 24-month cheese, 1 of 21 did. Our cards do not say whether the Parmesan on your shelf contains lysozyme, so read the label and take the question to your allergist. In the United States a cheese sold as Parmesan must hold no more than 32 percent moisture and be cured for at least 10 months. Even basic composition is less certain than a label suggests: two Brazilian food tables put its cholesterol at 100.7 and 68 mg per 100 g, 48 percent apart. Some questions have no answer here at all. None of the studies we found measured what the salt does, or looked at pregnancy, kidney disease, or adults with lactose intolerance, so if one of those is your reason for asking, this page cannot settle it and your doctor or dietitian can.

Sources

1. parm-b2-11 · regulation
   It contains not more than 32 percent of moisture, and its solids contain not less than 32 percent of milkfat, as determined by the methods prescribed in § 133.5 (a), (b), and (d). ... It is cured for not less than 10 months.
   21 CFR 133.165, Parmesan and reggiano cheese (eCFR) · checked 2026-09-23
2. parm-b2-05 · RCT
   In 16 T2D patients, we measured plasma AA levels through the course of two 75-g oral glucose tolerance tests (OGTT) preceded by either 500-ml water or a high-protein nutrient preload (50-g Parmesan cheese, one boiled egg, and 300-ml water). ... Plasma AA levels were 24% higher after the nutrient preload (p < 0.0001). This increment was directly proportional to both the enhancement of beta cell function (r = 0.58, p = 0.02)
   Eur J Nutr, 2019 · checked 2026-09-23
3. parm-b2-01 · meta-analysis of RCTs
   A total of 12 randomized controlled trials (RCTs) were identified that examined the effect of cheese consumption on blood lipids and lipoproteins in healthy adults. ... A meta-analysis of 5 RCTs that compared the effects of hard cheese and butter, both of which had a similar ratio of polyunsaturated fatty acids to saturated fatty acids (P/S ratio), was performed. ... Compared with butter intake, cheese intake (weighted mean difference: 145.0 g/d) reduced low-density lipoprotein cholesterol (LDL-C) by 6.5% (-0.22 mmol/l; 95%CI: -0.29 to -0.14) and high-density lipoprotein cholesterol (HDL-C) by 3.9% (-0.05 mmol/l; 95%CI: -0.09 to -0.02) but had no effect on triglycerides.
   Nutr Rev, 2015 · checked 2026-09-23
4. parm-b2-02 · meta-analysis of RCTs
   Eligible human randomized controlled trials (RCTs) investigated the effect of isoenergetic substitution of hard or semi-hard cheese with other dairy products on blood lipid markers. ... Pooled analyses of 7 RCTs showed a reduction in fasting total cholesterol, LDL-C and HDL-C concentrations after ≥14 d mean daily intake of 135 g cheese (weighted mean difference [WMD]: -0.24 mmol/L; 95% confidence interval (CI): -0.34, -0.15; I2 = 59.8%, WMD: -0.19 mmol/L; 95% CI: -0.27, -0.12; I2 = 42.8%, and WMD: -0.04 mmol/L; 95% CI: -0.08, -0.00; I2 = 58.6%, respectively) relative to ∼52 g/d butter.
   Adv Nutr, 2023 · checked 2026-09-23
5. parm-b2-03 · RCT
   The objective was to compare the effects of diets of equal fat content rich in either hard cheese or butter or a habitual diet on blood pressure and fasting serum blood lipids, C-reactive protein, glucose, and insulin. ... The study was a randomized dietary intervention consisting of two 6-wk crossover periods and a 14-d run-in period during which the subjects consumed their habitual diet. The study included 49 men and women who replaced part of their habitual dietary fat intake with 13% of energy from cheese or butter. ... Cheese lowers LDL cholesterol when compared with butter intake of equal fat content and does not increase LDL cholesterol compared with a habitual diet.
   Am J Clin Nutr, 2011 · checked 2026-09-23
6. parm-b2-07 · RCT
   Thirty mild-moderate hypertensive patients, with BP values not on target (> 140 and/or > 90 mmHg) after at least 3 months of stable treatment were considered in this randomized, double-blind placebo-controlled cross-over study. All patients randomly received a dietary integration (30 g/day) of Grana Padano cheese or a placebo (made from flavored grated bread mixed with fats and salts in concentrations equal to those of the cheese). BP was evaluated at baseline and at the end of the active and placebo treatments (2 months each) ... The mean decrease (vs. placebo) for 24-hour ABP was -3.5 mmHg for systolic and -2.4 mmHg for diastolic BP (p = 0.0063 and p = 0.0065, respectively).
   Eur Rev Med Pharmacol Sci, 2018 · checked 2026-09-23
7. parm-b2-09 · cohort
   Nine oral-healthy adults were instructed to eat 25 gr of GP cheese for 5 consecutive days. ... GP cheese significantly modifies oral pH, causing a shift toward basic conditions which are kept for a few hours.
   J Transl Med, 2022 · checked 2026-09-23
8. parm-b2-06 · RCT
   When lysozyme-sensitized children received 12-months aged and lysozyme-containing cheese, several immediate and late adverse reactions such as itching, abdominal pain, vomiting, nausea, dermatitis, rhinitis, bronchial asthma, urticaria, and angioedema were seen in 5 out of 21 subjects; only 1 out of 21 children showed an adverse reaction after challenge with 24-months-ripened lysozyme-containing cheese.
   Eur J Nutr, 2013 · checked 2026-09-23
9. parm-b2-10 · case report
   The Parmigiano Reggiano cheese shows a high concentration of easily absorbed amino acids and oligopeptides like a hydrolyzed proteic preparation. ... Finally, another relevant characteristic of Parmigiano Reggiano cheese is the complete absence of lactose.
   Acta Biomed, 2008 · checked 2026-09-23
10. parm-b2-04 · RCT
    Eight well-controlled T2D patients, aged 40-70 years, were randomized to consume a 'preload' of either water or non-glucidic nutrients (50g of Parmesan cheese, one boiled egg) 30min before a 300-min oral glucose tolerance test. RESULTS: After the nutrient preload, significant reductions were observed in peak glucose (-49%; P<0.02)
    Diabetes Metab, 2016 · checked 2026-09-23
11. parm-b2-08 · cross-sectional
    According to Unicamp table, the cholesterol content found in parmesan cheese was 100.7 mg/100 g, while it was 68 mg/100 g in UNIFESP table, that is, a 48% (p < 0.05), higher content in the former.
    Rev Assoc Med Bras (1992), 2011 · checked 2026-09-23