Ricotta cheese: two small trials about muscle, and a lot of borrowed evidence

Most of what gets said about ricotta is borrowed from the protein it is made of. The strongest study here is a meta-analysis of 18 randomized tracer trials in 602 people, and it tested whey protein swallowed as a drink rather than cheese eaten as food. Whey delivered 57 percent of its phenylalanine into the blood over 5 hours (SD 10), against 45 percent for casein and 65 percent for milk protein (P < 0.001). Older participants absorbed 45 percent where young ones absorbed 51. The cheese itself has been fed to people twice, both times in Mexico, both times at 210 g a day. In 100 men and women over 60 who did not have sarcopenia, 12 weeks of that produced 1.3 lb (0.6 kg) more appendicular muscle mass while the control group lost 2.2 lb (1.0 kg) (between-group P = 0.009). Those controls ate as usual, so the trial compares adding food with changing nothing, and the standard deviations of 7.7 and 5.7 lb (3.5 and 2.6 kg) are wider than either figure. Ricotta is also a fresh soft cheese, the kind CDC tells pregnant women, people 65 or older and people with weakened immunity to avoid unless it is heated until steaming hot.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

What your body absorbs

• Whey protein, which is what ricotta is made of, delivered 57% of its phenylalanine into the blood over 5 hours against 45% for casein. — 602 participants in 18 randomized trials using intrinsically labeled whey, casein or milk protein; whey arm 137 people (n = 602) Evidence A source
  57% (SD 10) of dietary protein-derived phenylalanine in the circulation for whey against 45% (SD 11) for casein and 65% (SD 13) for milk protein, P < 0.001; 45% in older against 51% in young people
• Women who cannot digest lactose ate 34 g of lactose a day from dairy and reported more gas but no more bloating, pain or diarrhea than on the lactose-free version. — 62 women, 31 with lactose maldigestion and 31 without, one week per phase, double-blind randomized crossover (n = 62) Evidence B source
  Significantly increased flatus frequency and perceived rectal gas on 34 g lactose per day; bloating, abdominal pain, diarrhea and overall symptom severity not significantly different from 2 g lactose per day

What cooking and storage change

• For people at higher risk of Listeria, CDC lists fresh soft cheeses such as requesón and queso blanco as foods to avoid when unheated, even if made with pasteurized milk. Heating them to 165°F (74°C) or until steaming hot moves them to the safer column. — people at higher risk for Listeria: pregnant, 65 or older, weakened immune system Evidence E source
  Avoid unheated queso fresco-type and similar fresh soft cheeses such as queso blanco and requesón even when pasteurized; safer when heated to 165°F or until steaming hot
• FDA warns that Listeria can grow in the fridge, so the longer a contaminated ready-to-eat food is kept, the more it can grow. It advises keeping the refrigerator at 4°C (40°F) or below and notes that freezing does not kill the bacteria. — households storing ready-to-eat refrigerated foods Evidence E source
  Listeria grows at refrigeration temperatures; longer storage gives more growth; keep the refrigerator at 40°F (4°C) or below; freezing does not eliminate it
• Laboratory data suggest Listeria grows fast in fresh ricotta: challenge tests in eight brands showed rapid growth, and the acids in the cheese did not hold it back. — eight brands of fresh ricotta, storage 39 to 69 °F (4.1 to 20.6 °C) (n = 8 brands) Evidence D source
  Rapid growth of L. monocytogenes in all eight brands; organic acids showed no anti-listerial effect in ricotta

What it does to your health

• Adding 7.4 oz (210 g) of ricotta a day for 12 weeks moved appendicular muscle mass by 1.3 lb (0.6 kg) up in older adults while the control group lost 2.2 lb (1.0 kg). — 100 men and women over 60 without sarcopenia, Mexico, 12 weeks, single-blind randomization (n = 100) Evidence B source
  Appendicular skeletal muscle mass +1.3 lb (0.6 kg) (SD 3.5) against -2.2 lb (-1.0 kg) (SD 2.6) in controls, between-group P = 0.009
• A systematic review of dairy and aging names ricotta as the food behind the muscle mass finding, while calling the whole evidence base scarce. — 6 studies, 5 prospective cohorts and 1 randomized trial, in community-dwelling older people (n = 6 studies) Evidence C source
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• In 802 Sicilian adults, habitual ricotta intake went with higher LDL cholesterol while milk intake went with lower, even though total dairy intake showed no link at all. — 802 healthy adults from a population-based cohort in Palermo, statin users and people with diabetes or heart disease excluded (n = 802) Evidence C source
  Ricotta intake positively associated with LDL cholesterol (p < 0.001) and milk intake inversely associated (p < 0.005) in multivariate regression; no correlation for total dairy
• Pooling over a million women, eating 0.88 oz (25 g) a day or more of cottage or ricotta cheese went with a 15% lower rate of estrogen-receptor-negative breast cancer and no change in breast cancer overall. — over 1 million women in 21 cohorts followed up to 8 to 20 years, 37861 invasive breast cancers (n = 37861 cases) Evidence C source
  Pooled HR 0.85 (95% CI 0.76 to 0.95) for ER-negative tumors comparing 25 g/d or more with under 1 g/d; no clear association overall

Safety, limits and interactions

• A US Listeria outbreak announced in 2026 and linked to requesón, a soft ricotta-type cheese, made 15 people ill in 4 states, put 14 in hospital and killed 1. CDC notes that fresh soft cheeses made with pasteurized milk have caused outbreaks, this one included. — US multistate Listeria outbreak linked to requesón/soft ricotta cheese, 4 states, closed August 2026 (n = 15) Evidence E source
  15 cases, 14 hospitalizations, 1 death, 4 states; fresh soft cheese made with pasteurized milk
• Across 100 surveys, Listeria monocytogenes turned up in 2.4% of soft cheese samples (95% CI 1.6 to 3.6), the category that fresh cheeses such as ricotta belong to. — 100 prevalence studies with at least 100 samples each, covering deli meat, soft cheese and packaged salad (n = 100 studies) Evidence C source
  Soft cheese 2.4% (95% CI 1.6 to 3.6); deli meat 2.9% (95% CI 2.3 to 3.6); packaged salad 2.0% (95% CI 1.2 to 3.1)

Who this works differently for

• CDC says about 1 in 25,000 pregnant women in the US get Listeria each year, and 1 in 4 of them lose the pregnancy or the baby shortly after birth. — pregnant women in the United States Evidence E source
  About 1 in 25,000 pregnant women infected each year; 1 in 4 of those lose the pregnancy or the baby shortly after birth
• CDC says more than half of US Listeria infections occur in people 65 and older and 75% in people with a weakened immune system. In both groups infection almost always means hospital, and about 1 in 6 die. — people 65 years or older and people with a weakened immune system, United States Evidence E source
  Over half of infections in people 65 and older, almost always hospitalized, 1 in 6 die; weakened immunity 75% of infections, almost always hospitalized, 1 in 6 die
• FDA says pregnant women, older people and people with weakened immunity should not eat unpasteurised milk products or any queso fresco-type cheese. Listeriosis that is mild in a pregnant woman can still lead to miscarriage and stillbirth. — pregnant women, the elderly, and those with weakened immune systems Evidence E source
  Advised not to eat unpasteurized milk products or any queso fresco-type cheeses; in pregnancy listeriosis can lead to miscarriage and stillbirth even when mild in the mother
• In people who already had sarcopenia, the same 7.4 oz (210 g) of ricotta a day for 3 months did not change muscle mass overall, and only the men gained, by 270 g. — 40 sarcopenic men and women over 60, Mexico, 3 months (n = 40) Evidence B source
  No significant between-group change in total appendicular skeletal muscle; men in the intervention group gained 270 g and improved fasting insulin (P = 0.05)

The bottom line

The second trial is the one that complicates the first. In 40 people over 60 who already had sarcopenia, the same 210 g a day for three months changed total appendicular muscle not at all. Only the men gained, by 270 g, and that came out of a secondary analysis in a trial where 12 of 20 people finished the ricotta arm. A systematic review of dairy and aging names ricotta as the food behind the muscle finding and calls the evidence base scarce, which is fair. It rests on six studies, five of them cohorts, spread across three separate outcomes. So the honest summary is that a large daily portion of a high-protein food may help older people hold on to muscle. It rests on one small trial against an inactive comparison, and in people who had already lost muscle it did not work. Two observational findings sit on opposite sides of the ledger, and neither can show cause. In 802 healthy adults in Palermo, with statin users and people with diabetes or heart disease excluded, reported ricotta intake was associated with higher LDL cholesterol (p < 0.001) while milk intake was associated with lower (p < 0.005). Total dairy intake showed no association at all, and intake came from a questionnaire. Pooling 21 cohorts covering over a million women and 37861 invasive breast cancers, eating 0.88 oz (25 g) a day or more of cottage or ricotta cheese went with a 15 percent lower rate of estrogen-receptor-negative tumors (HR 0.85, 95% CI 0.76 to 0.95). There was no clear association with breast cancer overall, that is one tumor subtype among many comparisons, and cottage cheese was counted together with ricotta. Safety is where the cheese itself matters most, because ricotta is a fresh soft cheese and that is the category Listeria travels in. Across 100 prevalence surveys, Listeria monocytogenes was found in 2.4 percent of soft cheese samples (95% CI 1.6 to 3.6), though the authors warn that the studies varied too much for a single global number to be used in risk assessment. A US outbreak announced in 2026 and linked to requesón, a soft ricotta-type cheese, made 15 people ill in 4 states, put 14 in hospital and killed 1. CDC notes that fresh soft cheeses made with pasteurized milk have caused outbreaks, this one included. In laboratory challenge tests Listeria grew rapidly in all eight brands of fresh ricotta tested, and the acids in the cheese did not hold it back. FDA notes that the longer a contaminated ready-to-eat food is kept in the fridge the more it can grow, that freezing does not kill it, and that the fridge should be at 4°C (40°F) or below. The people for whom this matters are pregnant women, people 65 or older and anyone with a weakened immune system. CDC says about 1 in 25,000 pregnant women in the US get Listeria each year and 1 in 4 of them lose the pregnancy or the baby shortly after birth. In older people and people with weakened immunity, infection almost always means hospital and about 1 in 6 die. For these groups CDC lists unheated fresh soft cheeses such as requesón and queso blanco among foods to avoid, even when made with pasteurized milk. Heating them to 74°C (165°F) or until steaming hot moves them to the safer column. FDA tells the same groups not to eat unpasteurised milk products or any queso fresco-type cheese. Neither agency uses the word ricotta in that advice, and we found no study of ricotta in children. There is nothing in the American or European claim registers under its name either. Lactose is the other open edge. In 62 women, half of them lactose maldigesters, eating 34 g of lactose a day for a week raised flatus frequency and the sense of rectal gas, while bloating, abdominal pain, diarrhea and overall symptom severity were no worse than on 2 g a day. That lactose came from milk, cheese and yogurt, not from ricotta.

Compared with other foods

Sources

1. rict-r3-07 · meta-analysis of RCTs
   Casein ingestion resulted in a smaller (45% ± 11%), whey protein ingestion in an intermediate (57% ± 10%), and milk protein ingestion in a greater (65% ± 13%) fraction of dietary protein-derived phenylalanine appearing in the circulation (P < 0.001).
   J Nutr, 2020 · checked 2026-09-24
2. rict-r3-08 · randomized controlled trial
   Women with lactose maldigestion reported significantly increased flatus frequency and subjective impression of rectal gas during the period of high lactose intake; however, bloating, abdominal pain, diarrhea, and the global perception of overall symptom severity were not significantly different between the 2 treatment periods.
   Am J Clin Nutr, 1998 · checked 2026-09-24
3. hf2-rict-4 · Agency guidance
   Any unheated queso fresco-type cheeses, when made with pasteurized or unpasteurized (raw) milk, such as queso fresco, or similar fresh, soft cheeses such as queso blanco and requesón. ... Queso fresco-type cheeses or unpasteurized (raw) milk cheeses when heated to 165°F or until steaming hot
   CDC, Preventing Listeria Infection, Safer Food Choices · checked 2026-10-08
4. hf2-rict-6 · Agency guidance
   The longer ready-to-eat refrigerated foods contaminated with L. monocytogenes are stored in the refrigerator, the more opportunities there are for this pathogen to grow. To slow down or prevent the growth of L. monocytogenes, keep the refrigerator at 40° F (4° C) or below, and the freezer at 0° F (-18° C). ... Unlike most bacteria, L. monocytogenes can grow at refrigeration temperatures and freezing will not eliminate or reduce the pathogen.
   US Food and Drug Administration, Listeria (Listeriosis) · checked 2026-10-08
5. hf2-rict-7 · laboratory challenge test
   Challenge tests with eight brands of fresh ricotta showed rapid growth of Listeria monocytogenes and significant variability in physical-chemical characteristics. ... Interestingly, a lack of anti-listerial effect of organic acids in ricotta was observed in this study.
   Food Microbiology, 2019 · checked 2026-10-08
6. rict-r3-01 · randomized controlled trial
   ASMM increased in the IG/HD + RCH (0.6±3.5 kg), but decreased in the CG/HD (-1.0±2.6). The relative change between groups was statistically significant (P=0.009).
   Clin Interv Aging, 2014 · checked 2026-09-24
7. rict-r3-03 · systematic review
   The consumption of dairy products by older people may reduce the risk of frailty, especially with high consumption of low-fat milk and yogurt, and may also reduce the risk of sarcopenia by improving skeletal muscle mass through the addition of nutrient-rich dairy proteins (ricotta cheese) to the habitual diet.
   Adv Nutr, 2019 · checked 2026-09-24
8. rict-r3-04 · cohort study
   However, multivariate analyses showed an inverse association between serum LDL-C and milk intake as well as a positive association between ricotta cheese intake and LDL-C concentrations.
   Nutrients, 2021 · checked 2026-09-24
9. rict-r3-05 · pooled cohort analysis
   differences by ER status were suggested for yogurt and cottage/ricotta cheese with associations observed for ER-negative tumors only (pooled HR = 0.90, 95% CI: 0.83, 0.98 comparing ≥60 g/d with <1 g/d of yogurt and 0.85, 95% CI: 0.76, 0.95 comparing ≥25 g/d with <1 g/d of cottage/ricotta cheese)
   Am J Clin Nutr, 2021 · checked 2026-09-24
10. hf2-rict-5 · Outbreak notice
    Cases: 15 ... Hospitalizations: 14 ... Deaths: 1 ... States: 4 ... Be aware that fresh soft cheeses made with pasteurized milk have caused Listeria outbreaks, including this one. ... For pregnant women, Listeria can cause pregnancy loss, premature birth, or a life-threatening infection in newborns.
    CDC, Listeria Outbreak Linked to Requesón/Soft Ricotta Cheese, June 2026 (updated Aug. 26, 2026) · checked 2026-10-08
11. rict-r3-06 · meta-analysis of prevalence studies
    we estimated L. monocytogenes prevalence in deli meat at 2.9% (95% confidence interval [CI], 2.3 to 3.6%), in soft cheese at 2.4% (95% CI, 1.6 to 3.6%), and in packaged salad at 2.0% (95% CI, 1.2 to 3.1%)
    J Food Prot, 2019 · checked 2026-09-24
12. hf2-rict-1 · Agency guidance
    Every year in the United States, about 1 in 25,000 pregnant women are infected with Listeria. ... Sadly, 1 in 4 pregnant women who get this illness lose their pregnancy or their baby shortly after birth.
    CDC, Listeria infection, people at risk: protect your pregnancy from Listeria · checked 2026-10-08
13. hf2-rict-2 · Agency guidance
    More than half of all Listeria infections occur among people 65 years and older. Older adults with Listeria infection almost always have to be hospitalized. Sadly, 1 in 6 older adults with this infection die. ... People with a weakened immune system make up 75% of all people with Listeria infection. Infection almost always leads to hospitalization. Sadly, 1 in 6 people in this group with Listeria infection die.
    CDC, Listeria infection, people at risk: protect your pregnancy from Listeria · checked 2026-10-08
14. hf2-rict-3 · Agency guidance
    While listeriosis can present as a mild disease in pregnant woman, the infection can lead to serious complications with their pregnancy, including miscarriage and stillbirth. ... Pregnant women, the elderly, and those with weakened immune systems should not eat certain foods, including unpasteurized milk and unpasteurized milk products, any queso fresco-type cheeses, raw and smoked fish, raw sprouts, and certain other raw foods, which carry a high risk for L. monocytogenes.
    US Food and Drug Administration, Listeria (Listeriosis) · checked 2026-10-08
15. rict-r3-02 · randomized controlled trial
    Secondary analysis showed that the men in the intervention group gained 270 g in TASM compared to those in the control group, and improved their fasting insulin levels (P = 0.05), muscle strength, lean body mass in the arms, and body weight variables.
    Clin Interv Aging, 2012 · checked 2026-09-24