Aged Cheese: Nutrients, What Research Shows and Safety

Aged cheese is milk that has been curdled, drained and then left to ripen, so that microbes keep changing it over weeks, months or years. This page covers four common hard and semi-hard cheeses: cheddar, Parmesan, Swiss and Gouda. Cheese counts as a fermented food, which the ISAPP expert panel defines as food made through desired microbial growth and enzyme action. A fermented food is not automatically a probiotic. [2] This page keeps the cheese you eat apart from supplements and from hype. It describes what research found; it is not a recommendation to eat any amount.

Read this first

• Cheese is a concentrated food. USDA lists about 114 kcal, 5.3 g of saturated fat (27% of the Daily Value) and 185 mg of sodium (8%) in 1 ounce (28.35 g) of cheddar. [1] Parmesan has far more sodium per 100 g than Swiss (1,175 mg versus 187 mg). [1]
• Pregnancy. Official advice differs by country. The NHS says hard cheeses such as cheddar and Parmesan are fine in pregnancy, even if unpasteurized, while soft mold-ripened and soft blue cheeses should be avoided unless cooked. [10] The CDC says any cheese made with raw milk should be avoided unless heated until steaming hot. [11] Ask your own clinician.
• Medicines. Aged cheese is on the MedlinePlus list of high-tyramine foods to ask about if you take an MAOI antidepressant such as tranylcypromine. [13]
• Milk allergy. Cheese is a milk food, so aged cheese is not safe for someone with a cow's milk allergy. For trouble breathing or swelling of the face, lips or throat, call 911 (or your local emergency number). [16]
• Evidence in one line: short trials show hard cheese raises LDL cholesterol less than butter does, but those trials used large amounts and measured blood markers, not heart attacks. [3]

What is in it (USDA values)

The values below are for cheddar (USDA FoodData Central item 173414, SR Legacy). [1] The serving column is the USDA household portion of 1 ounce, 28.35 g, which is about one slice. The serving figures are the 100 g values multiplied by 0.2835.

% Daily Value uses the FDA 2016 Daily Values; values vary with the cheese, the milk, the age and the maker. The USDA also lists vitamin D for these cheeses, but the numbers look unusually high for cheese, so we left them out until they can be checked.

The other three cheeses differ mostly in salt, fat and calcium (per 100 g, USDA SR Legacy): [1]

USDA also lists 0.99 g of total trans fat per 100 g in Swiss cheese. [1] We did not read a source on how much of this is the naturally occurring kind found in dairy, and the other three entries list no value.

Plant compounds are not the story here. What fermentation adds is mostly small molecules such as peptides and organic acids, and one 2026 review says these may affect digestion, immunity and heart risk but that results are hard to turn into consistent benefits because strains, processing and doses vary so widely. [17] That is a review of possibilities, not proof for cheese.

What research says

Eaten as food vs other products. All of the above is about natural cheese eaten as food. We did not read data for processed cheese slices, cheese spreads or cheese powders, which differ in salt and additives. Cheese is also not a replacement for medicines.

How much is a normal serving

The USDA household portion is 1 ounce (28.35 g, about one slice), which has about 114 kcal in the cheddar entry. [1] USDA also lists 1 cup of shredded cheddar as 113 g. [1] That is information from the USDA data, not a prescription. We could not open the MyPlate dairy page, so we do not quote its serving rule here. The WHO advises keeping saturated fat to no more than 10% of daily energy and salt under 5 g a day (2 g of sodium). [7] The FDA says the 2020-2025 Dietary Guidelines for Americans advise people 14 and older to keep sodium to 2,300 mg a day. [8] Cheese counts toward both limits.

Safety, allergy and medicines

• Saturated fat and the heart. The AHA advisory concluded that swapping saturated fat for unsaturated fat lowers heart disease risk. [6] Cheese has a lot of saturated fat per ounce (see the table), so people told to lower LDL cholesterol may be asked by their clinician to limit it.
• Sodium. Salt levels differ widely between cheeses. Parmesan has about six times the sodium of Swiss in the USDA data. [1] The FDA says average U.S. sodium intake is about 3,400 mg a day, well above the 2,300 mg limit. [8] People with high blood pressure or kidney disease should ask a clinician about cheese portions; see kidney disease: potassium and oxalates.
• Pregnancy and Listeria. The NHS says soft mold-ripened cheeses (such as brie and camembert) and soft blue cheeses should be avoided unless cooked until steaming hot, and that unpasteurized milk products should be avoided, while hard cheeses are fine. [10] The CDC says Listeria is rare but can be serious for pregnant people, newborns, adults 65 and older and people with weakened immune systems, and lists any cheese made with raw milk as one to avoid unless heated. [11] A university extension fact sheet likewise says soft cheeses should carry a "made with pasteurized milk" label, and lists hard cheeses as acceptable. [19]
• Raw milk. The CDC says raw milk can carry germs including Listeria, Salmonella and E. coli, and that children under 5, adults over 65, pregnant women and people with weakened immune systems face higher risk of serious illness. It applies the warning to products made from raw milk. [12] Check the label for "made with pasteurized milk".
• Tyramine and MAOI antidepressants. MedlinePlus says eating high-tyramine foods during treatment with an MAOI can cause a serious reaction, and names aged cheese among them; a doctor or dietitian says which to avoid. [13] This is a real medicine interaction. Ask your prescriber before eating aged cheese.
• Histamine and tyramine in cheese. A 2025 study of 125 ripened cheeses from Polish shops found tyramine in 28% (5.6 to 646 mg per kg) and histamine above 100 mg per kg in 11.2%; the authors said ripened cheeses can contain significant amounts and may pose a potential health risk. [14] A 2026 review found tyramine and histamine were the amines most often reported at high levels, and that ripening conditions and added cultures changed them. [15] Levels vary a lot between batches. See histamine, tyramine and fermented foods. We did not read a source giving safe amounts for people who react to histamine.
• Milk allergy. Cow's milk is one of the most common food allergens; a milk allergy is an immune reaction, different from lactose intolerance. Anaphylaxis is a medical emergency: call 911 for trouble breathing, throat swelling or fainting. [16] One review found some fermented foods may lower allergenicity, but the evidence was limited and most studies had weaknesses, so do not treat aged cheese as safe for milk allergy. [20]
• Lactose. NIDDK says yogurt and hard cheeses (examples given are cheddar and Swiss) are easier to tolerate than other dairy foods because they contain less lactose, and that many people can handle about 12 g of lactose at a time. [9] USDA lists total sugars (not lactose alone) of 0.0 to 2.2 g per 100 g in these four cheeses. [1]
• Medicines. Apart from MAOIs, we did not find a source describing a cheese-specific interaction. See foods and medicine interactions.
• Children and diabetes. We did not read a source on cheese for young children, so see foods for babies and toddlers. USDA lists only 3.4 g of carbohydrate per 100 g of cheddar, [1] but we did not find a trial of cheese and blood sugar in the sources we read.

Choosing, storing and food safety

• For pregnancy or a weakened immune system, look for "made with pasteurized milk" on the label. [11] [19]
• Compare Nutrition Facts labels: sodium and saturated fat differ a lot between cheeses. [1]
• We did not read a source on storage times or on cutting mold off cheese, so follow the label and a food safety source for that.

Related pages

• Histamine, tyramine and fermented foods
• Foods in pregnancy: what official bodies advise
• Foods and medicine interactions
• Food allergy basics and emergency signs
• Foods for cholesterol and heart health
• Yogurt