Cheese as a superfood? That sounds about as reasonable as having potato chips or gummy bears on the list. Yet somehow, cheese seems to be making a small comeback as more and more people tune in to some of its underappreciated yet distinct properties that could have important benefits for our health.
CHEESE: THE STORY
Cheese-making is as old as recorded history or perhaps even older. It’s thought that humans stumbled across cheese-making when they used the stomachs of animals, such as sheep, to transport milk (the world’s first biodegradable shopping bag?). It’s in the stomach of sheep, cows, and other animals that the enzyme rennet exists, which, we now understand, helps curdled milk (which naturally separates into curds and whey protein) coagulate into the gel that is young, unripened cheese. Our ancestors learned quickly that cheese had benefits that extended beyond milk, as it was more portable and had a longer shelf life than milk itself. By the time of the Roman Empire, cheese-making was well established in Europe, the Middle East, and parts of South Asia, with a reach extending as far east as Tibet.
The process of cheese-making requires the use of not only soured milk and rennet but also bacteria, which, through the aging process, give cheese its distinct flavours. The bacteria in cheese convert the natural milk sugar, lactose, into lactic acid, which means that cheese, especially aged hard cheeses, such as old cheddar, is less likely to trigger the bloating and stomach pain that are usually associated with lactose intolerance.
CHEESE: THE NUTRITION
When it comes to cheese, less is more. Although we might measure portions of milk, fruit, and vegetables in cups, the high calorie content of cheese means that serving sizes are usually just 30 grams (about an ounce) while Canada’s Food Guide uses a reference serving size of 50 grams, an amount that will provide you with about the same amount of calcium as a cup of milk or 3/4 cup of yogurt. For a 50-gram serving size, then, you can expect 201 calories and 17 grams of fat, of which almost 11 grams are the much-maligned saturated fats, along with 13 grams of protein. The top vitamins and minerals in cheese are calcium (357 mg, or 36% of your daily needs), vitamin A, vitamin B2, zinc, and selenium (11% of each). Since cheese is salted, it also tends to be fairly high in sodium, with about 300 mg (about 1/8 of your daily limit) per 50-gram serving.
CHEESE: THE SCIENCE
As a result of health recommendations to reduce our intake of saturated fat, which naturally occurs in dairy products, we’ve subsisted off of 0% yogurt (the percent reflects the percentage of calories from fat), skim milk (my Dutch friend calls this grey water), and low-fat cheese, the latter of which provides the culinary delights of chewing on a flat tire. More recently, however, researchers have been re-examining the data we have on dairy products, and the findings could turn nutrition upside down: If you look carefully at the available evidence, it is now being argued that there is actually no link between consuming full-fat dairy and the risk of heart disease. In fact, the opposite might be true: Higher-fat dairy (and in some cases, cheese specifically) could, seemingly paradoxically, be associated with a lower risk of cardiovascular disease.
If it turns out these findings are, in fact, true, it begs the question, how could we have been so wrong? A big part of the problem could be that cheese and full-fat dairy foods tend to be associated with a lower-quality diet, at least in the United States. When researchers looked at dietary patterns in the U.S. population, they found that full-fat dairy is more commonly consumed by people who are at a higher risk of heart disease and diabetes. Fair enough, but as it turns out, the same people who eat full-fat dairy in the United States are also more likely to smoke, be overweight, be inactive, and eat a lower-quality diet. If you go to Europe, on the other hand, eating full-fat dairy is a part of life and is actually associated with a higher-quality diet and healthier lifestyle. In other words, it might not be the cheese that’s the problem but rather the company it tends to keep. In the United States, that is more likely to be burgers on white buns, pop, and cigarettes; in Europe, it is greens, fruit, and red wine. The difference, healthwise, between these two diets is drastic.
Although there are some basic nutrients in cheese that are important for health, such as protein, calcium, and vitamin A, cheese also has an underappreciated but perhaps even more important ingredient that could play a vital role in human health, and that is bacteria. Cheese, like yogurt, is a fermented food product, which means bacteria are involved in its conversion from liquid milk to solid food. Unlike yogurt, however, the benefit from eating cheese is derived not from the live bacteria but rather from the by-products the bacteria produce during the aging process, most specifically vitamin K2, or more technically, menaquinone.
Vitamin K2 is a family of compounds of various sizes, ranging from MK1 (MK refers to menaquinone) to MK. We’ll get into vitamin K1 in the section on kale, but for now, let’s keep it to this: Vitamin K1, known as phylloquinone, long known as a vital factor for blood clotting, is also being lauded for its potential anti-inflammatory and insulin-modulating effects. Vitamin K2, however, is generating its own share of attention, especially for its potential role in heart health. Te turning point for vitamin K2 might have been in 2004, when Dutch researchers published a study suggesting that individuals with the highest intake of vitamin K2 had a 57% lower risk of dying of heart disease, and a 26% lower risk of dying from any cause, than those with the lowest intake. The high-vitamin-K2 group were also much less likely to have calcified arteries (arteries made rigid by the buildup of calcium) than groups with the lowest levels. Interestingly, vitamin K1, which is found mostly in green, leafy vegetables, was not associated with any of these benefits. A few years later, the same research team proposed what is known as a dose–response effect for vitamin K2 and heart health, meaning that as K2 intake increases, heart disease risk drops in a linear fashion (more precisely, for every 10 micrograms per day of vitamin K2 consumed, the odds of developing heart disease dropped by about 9%).
Why could vitamin K2 be so important for our hearts? The answer could lie with calcium. As mentioned, too much calcium in our arteries could leave us more prone to heart attacks, a fact that is a source of much irritation for women who are repeatedly told they need more calcium, only to see studies come out suggesting that too much calcium from supplements might actually increase the risk for heart attacks. According to the emerging theory, calcium, in a way, needs to be “told” where to go. That’s where vitamin K2 comes in: Its job is to direct calcium to the right places, namely to our bones, and not to the wrong places, namely our arteries. It does this by changing the way key proteins in our bones and our hearts work, through a process known as carboxylation. In our hearts, vitamin K2 carboxylates a key protein known as MGP (short for matrix Gla-protein—good news: there is no test on this), which prevents calcium from being laid down in our arteries, while in our bones, vitamin K2 carboxylates a protein known as calcitonin, which then activates bone-building cells known as osteoblasts. Sure enough, a systematic review and meta-analysis of seven studies found that vitamin K2 supplementation helped prevent bone loss and reduced risk of fracture. The effect of vitamin K2 might also explain why we see some inconsistencies in the vitamin D research: Vitamin D’s job is to help our bodies absorb calcium, but if we don’t have enough vitamin K2, then that calcium might not know where to go. It might not be enough to have one without the other.
But the intrigue doesn’t end there: There is also evidence that vitamin K2 could play a role in cancer prevention. U.S. researchers, for example, have made the connection between vitamin K2 and prostate cancer, while there is considerable research suggesting that dairy foods, and specifically high-fat ones, might be protective against colorectal cancer.
So, where do you get vitamin K2? Why, cheese, of course. Before you get too excited, however, the amount of vitamin K2 in cheese is far less than that found in the fermented Japanese soybean product natto (no doubt worthy of its own superfood section—save that for the next book), though they exist as different forms of vitamin K2 (natto typically provides MK7, while cheese provides MK8 and MK9), the implications for which are not yet entirely clear. Other smaller vitamin K2 sources include eggs (in the yolk), liver, beef, and chicken, and we also convert a small amount of vitamin K1 to K2 in our digestive tracts.
So, which cheeses should we eat? Again, we have much to learn. So far, it is suggested that aged and ripened cheeses, such as aged cheddar, Brie, and Gouda, provide the most vitamin K2. Young cheese, such as ricotta and mozzarella, may provide very little, if any. Processed cheese may contain very small amounts of vitamin K2, which might mean that if the cheese you eat comes from cheese slices, cheese spreads, pizza, nachos, or deep-fried cheese sticks, you might not be getting much vitamin K2 at all. These findings could help (finally) explain the French paradox, namely that the French, who routinely eat full-fat dairy foods and drink wine, tend to have a relatively low heart disease risk: They might be getting some of the benefit by enjoying quality cheeses with their meals.
THE BOTTOM LINE
As I said at the start of this book, my fear in labelling foods “superfood” is that we will unfairly elevate one food above another. In this case, I hope you will heed my words and not chase your next meal with a half-pound of double-cream Brie. Much of the evidence we have to date is built on correlations and associations rather than on the best kind of evidence that comes from randomized, controlled trials. It’s simply too early to give clear guidelines, and it’s also worth noting that, in the Dutch study mentioned earlier, those with the highest intake of vitamin K2 also had a higher body weight. Yes, good-quality cheese might be delicious and, as it turns out, more nutritious than we once thought, but it is still calorie dense, meaning that if you want to add it to your diet, you need to do it in place of something else.