Last week I mentioned something in passing that seemed to grab attention: during my time in Iceland I noticed many people with broad, well-developed jaws—quite different from what I often see in the U.S.
In Iceland, dairy is not demonized; it’s celebrated and produced in ways that differ from most American grocery options.
Typical Icelandic dairy tends to be:
- Full-fat
- Pasture-raised
- Minimally processed
- Often fermented (skyr, raw cheese, cultured butter)
Compare that with much of the U.S. market: homogenized, pasteurized, and often low-fat—products that can be stripped of fat-soluble nutrients and enzymes.
So what in these traditional dairy foods might influence stronger jaw development? The fat in full-fat dairy carries three important fat-soluble vitamins—A, D, and K2. These vitamins are key regulators of bone growth, mineral utilization, and immune function. Together they shape facial development in precise ways that modern diets often overlook.
- Vitamin A supports proper cell differentiation and the health of epithelial linings in the mouth, sinuses, and airways. It also plays a role in osteoblast activity, the cells responsible for building bone.
- Vitamin D enhances calcium absorption in the gut and helps ensure calcium reaches the bloodstream.
- Vitamin K2 acts like a traffic cop for calcium, activating proteins such as osteocalcin and matrix GLA protein (MGP) that direct calcium into bone and away from arteries, kidneys, and soft tissues.
In practical terms: a child eats a slice of cultured, full-fat cheese. That cheese provides calcium plus vitamins A, D, and K2. Vitamin D helps the calcium be absorbed, K2 guides it into developing jaws and palates instead of soft tissues, and vitamin A helps keep oral and airway tissues healthy and structurally sound.
Remove the fat and you remove the delivery system for those nutrients. Fat enables absorption of A, D, and K2—without it these vitamins don’t move effectively from food into the bloodstream. If a child also lacks the microbiome to convert K1 to K2 or isn’t getting preformed K2 from fermented foods or animal sources, development can be left to chance.
The risk goes beyond underdevelopment. Without enough K2 to activate MGP, calcium absorbed under the influence of vitamin D can deposit in the wrong places—arterial walls, kidneys, and soft tissues—contributing over time to calcification and related health problems.
K2 is essential for guiding calcium into bone rather than into plaque. Adults benefit as well: these vitamins support bone density, healthy gums, and robust immune barriers. But the critical window for skeletal and facial growth is childhood, which makes nutrient-dense full-fat and fermented dairy especially important for young families.
Iceland’s traditional diet appears to provide both dietary K2 and fermented foods that support a healthy gut microbiome. Fermented dairy and fish supply nutrients and microbial diversity that help optimize absorption and utilization of fat-soluble vitamins. The country’s mineral-rich volcanic soil further enhances the nutrient profile of food grown there.
There’s another factor many people don’t know about: a specific fatty acid found predominantly in ruminant fat called C15:0 (pentadecanoic acid). It’s an odd-chain saturated fat present mainly in the fat of cows, sheep, and goats. While foods like avocado, olive oil, and coconut contain beneficial fats, they don’t provide C15:0. This is not about fat in general but about a particular nutrient from a specific source.
C15:0 has shown promising effects in early studies—anti-inflammatory properties, mitochondrial support, and cellular resilience. Though most research so far comes from animal studies and small human trials, data suggest C15:0 may modulate inflammation and strengthen cell membranes, including those in gum tissue, which can influence oral health.
For oral health specifically, C15:0 has been associated with reductions in several pro-inflammatory markers linked to gum inflammation and bone loss. While the research is still evolving, the potential benefits are worth noting, especially because modern diets have greatly reduced intake of this fatty acid.
One analysis of U.S. dietary intake found that most people consume well below levels thought to be beneficial, largely because of the shift away from whole-fat dairy toward low-fat or processed alternatives over recent decades. Unless you regularly consume pasture-raised full-fat dairy, your intake of C15:0 is likely low.
Rather than overhaul my entire diet, I chose a practical approach: I supplement to restore specific nutrients that are hard to get consistently. For those avoiding dairy or with limited access to pasture-raised products, supplementation can be a realistic way to reintroduce C15:0 without large increases in calorie intake.
If you’re dairy-free, supplementation may mimic some of the anti-inflammatory and membrane-supporting effects of food-based C15:0. However, supplements don’t yet replicate the full synergy of whole foods—especially combined cofactors like vitamins A and K2—so whole, fermented foods remain ideal where possible.
For families raising children, this is a strong argument for bringing back nutrient-dense full-fat foods like butter and properly fermented cheeses. In my own practice and home life I regret following the low-fat trend for so long; it led to avoiding real butter and other valuable foods for years. Today there are clinical tools—such as MARPE and palatal expansion—that can help address airway and jaw issues later in life, but building a strong nutritional foundation early is preferable.
I keep raw sheep or goat cheese in rotation because it delivers K2, trace C15:0, beneficial microbes, and fat-soluble nutrients in one tasty bite. Cheese also helps neutralize acids in the mouth, reducing enamel erosion and supporting healthier oral pH—an enjoyable and effective way to protect teeth with food.
If you’re a healthcare professional or caregiver interested in providers who understand the mouth’s full-body connections, there are directories and continuing education options to help you find or become trained in functional dental care. These approaches are increasingly in demand and can make a meaningful difference in airway, facial balance, and long-term oral health.
P.S. Remember when skim milk was promoted as the healthier option? That advice may have contributed to decades of missed opportunities around oral development, fat-soluble nutrients, and inflammation. Consider sharing this perspective with someone who still believes skim milk is always better.
Hope you have a wonderful weekend. I’d love to hear what you think of this newsletter and what topics you’d like covered next.
Dr. B (Mark)