The Core Role of Enzymes in Cheesemaking
Enzymes are fundamental to the process of turning milk into cheese. The most well-known of these is rennet, a coagulant that causes milk to separate into solid curds and liquid whey. Rennet is primarily an enzyme complex containing chymosin, which acts on the milk protein casein to trigger coagulation. Without this enzymatic action, the characteristic texture of most cheeses would not be possible.
Types of Rennet and Their Sources
The source of rennet is a key distinction in cheesemaking, with implications for dietary preferences and potentially for health. The main types include:
- Animal Rennet: Traditionally sourced from the stomach lining of young, unweaned calves, lambs, or goats. It is a byproduct of the meat industry and contains natural chymosin and other enzymes like pepsin.
- Microbial Rennet: Produced by fermenting molds, such as Rhizomucor miehei. This type is widely used, particularly in the United States, as a cost-effective and vegetarian-friendly alternative to animal rennet. While the molds themselves are purified out, the process raises some concerns about potential byproducts.
- Vegetable Rennet: Derived from plants containing coagulating properties, such as artichoke thistle, fig tree bark, or nettles. This is used in certain traditional cheeses but can be less predictable and sometimes impart bitterness.
- Fermentation-Produced Chymosin (FPC): Often labeled simply as "enzymes," this is a genetically engineered (GMO) version of chymosin. Scientists implant the chymosin gene from a calf's stomach into a yeast or bacterial culture, which then produces the enzyme. This is widely used in commercial cheese production and is a source of controversy due to its GMO nature and lack of long-term studies on potential health impacts.
Health-Boosting Enzymes: The Probiotic Power of Aged Cheese
While rennet is a production enzyme, the true digestive health benefits often come from a different set of enzymes and beneficial bacteria known as probiotics. Aged and fermented cheeses contain live cultures that survive the cheesemaking process and contribute positively to gut health.
Benefits of Probiotics in Cheese
- Improved Digestion and Gut Microbiome: Probiotics help to balance the gut microbiome, which is vital for proper digestion and nutrient absorption. A healthy gut can lead to reduced inflammation and improved immune function.
- Potential for Managing Metabolic Health: Some studies suggest probiotic cheese can be beneficial in managing metabolic syndrome, with one pilot study showing reductions in BMI and blood pressure in obese hypertensive patients.
- Oral Health: Probiotic cheeses may also play a role in oral health. A study found a specific probiotic cheese helped reduce Candida colonization in denture wearers.
Bioactive Peptides and Protein Digestion
Beyond probiotics, the cheese ripening process, driven by enzymes from rennet and starter cultures, breaks down milk proteins (casein) into smaller, bioactive peptides. These peptides may have additional health benefits, including antimicrobial and antioxidant properties. The digestion of cheese protein is also higher in cured varieties, as the proteins are already partially broken down.
Important Health Considerations and Risks
While cheese offers benefits, it is not without potential downsides, and careful selection is important for health.
Concerns with Genetically Engineered Rennet
The widespread use of FPC, or genetically modified rennet, raises concerns for some consumers. Critics worry about potential allergens, toxins, or effects on the gut microbiome from the GM microorganisms used to produce the enzyme. In the US, it is labeled as GRAS (Generally Recognized As Safe), but some argue that long-term studies are lacking.
Biogenic Amines and Intolerance
During cheese ripening, certain enzymes can cause the breakdown of amino acids into biogenic amines, such as tyramine and histamine. In some individuals, particularly those sensitive to these compounds, this can cause adverse reactions like headaches or digestive issues. Cheeses heavily contaminated with spoilage bacteria are more likely to contain high levels of these amines.
Managing Lactose Intolerance with Cheese
Lactose intolerance is caused by a deficiency of the lactase enzyme, which breaks down milk sugar. However, many aged cheeses contain very little to no lactose because the live cultures consume it during fermentation and aging. This makes hard, aged cheeses, like Parmesan and aged cheddar, often well-tolerated by individuals with lactose intolerance.
Table: A Quick Guide to Cheese Enzymes and Health
| Cheese Type | Primary Enzymes/Cultures | Lactose Content | Potential Health Benefit | Health Concern |
|---|---|---|---|---|
| Aged Cheddar | Rennet (varied), Probiotics | Very low | Probiotics aid gut health; High in calcium | High in saturated fat and sodium |
| Swiss (Aged) | Rennet (varied), Probiotics | Very low | Probiotics and calcium | High in sodium |
| Fresh Mozzarella | Rennet (varied), Cultures | Higher than aged cheese | Excellent source of protein and calcium | Higher lactose for some intolerances |
| Parmesan | Rennet (varied), Probiotics | Virtually none | Bioactive peptides, high protein, very low lactose | High in sodium; some contain GMO rennet |
| Blue Cheeses | Rennet (varied), Probiotics | Very low | Diverse bacterial cultures, some probiotic | Potential Listeria risk if unpasteurized; Biogenic amines |
| Cottage Cheese | Rennet (varied), Probiotics (if labeled) | Variable | Good source of protein; Probiotic if cultures added | Higher lactose than aged cheeses; high sodium |
How to Choose the Healthiest Cheese
Here are a few tips to help you make informed choices about the cheese you eat:
- Prioritize Aged Varieties: Aged cheeses like cheddar, Swiss, and Gouda have lower lactose content and often contain more probiotics than fresh cheeses.
- Read the Label for Probiotics: Look for "live cultures" or "probiotics" on the label for fermented cheeses like cottage cheese or some Goudas.
- Be Mindful of Rennet Sources: If you have concerns about GMOs, look for products labeled with specific rennet types (e.g., "animal rennet" or "vegetable rennet") or vegetarian options. If only "enzymes" is listed, it is likely genetically engineered.
- Choose Raw Milk Cheeses with Caution: Raw milk cheeses can contain different beneficial digestive enzymes and bacteria than pasteurized varieties, but they carry a higher risk of Listeria and other pathogens. Ensure you are comfortable with the source.
- Moderation is Key: Remember that cheese is calorie-dense and high in saturated fat and sodium. Enjoy it as part of a balanced diet rather than a primary health food source.
Conclusion
So, are enzymes in cheese healthy? The answer is nuanced. The enzymes used for coagulation, like rennet, are generally safe but can have different origins, including genetically modified sources that cause concern for some. However, the enzymes and live cultures (probiotics) from the fermentation and aging process in many cheeses can significantly benefit gut health, aid digestion, and offer additional nutritional advantages like bioactive peptides and high calcium. Individuals with lactose intolerance can also benefit from aged cheeses with very low lactose content. Ultimately, the healthiest choice depends on the cheese type, its specific enzymes, and your individual health needs. Making an informed decision by checking labels and understanding the cheesemaking process is the best way to enjoy cheese while prioritizing your wellness.
Learn more about the health benefits of probiotics, including those in cheese, from Harvard Health
