Written by: Jyoti Madhusoodanan, Ph.D. | Issue # 111 | 2022
- Some kinds of cheese are rich in vitamin K, a nutrient essential to healthy bones.
- Daily consumption of Jarlsberg cheese, but not Camembert, improved several circulatory protein markers of bone health.
- More studies are needed to confirm if Jarlsberg cheese could act as a preventive remedy for osteoporosis.
When treating osteoporosis, a condition where bones become brittle and prone to fractures, doctors usually recommend dietary supplements containing vitamin D, vitamin K2, and calcium. Although milk and milk products are typically rich in these nutrients, cheese is unique in its vitamin K2 content, since the bacteria used in fermentation can produce variants of this nutrient that may be more efficiently absorbed and used by human tissues. The vitamin K2 content of cheese varies depending on the bacterial strains used; the Norwegian cheese Jarlsberg, for instance, is made by lactic acid bacteria that produce a version of vitamin K2 known as MK-9 in high quantities.
In a new study, Helge Einar Lundberg of Skjetten Medical Center in Norway and his colleagues tested whether eating a daily dose of Jarlsberg could boost markers of bone health in healthy women. Before embarking on a clinical trial, the team confirmed that eating about 57 grams of cheese in one day—approximately 4–6 slices of Jarlsberg—increased circulating vitamin K2 concentrations and serum osteocalcin, a blood biomarker of bone health .
The team then recruited 68 healthy, premenopausal women between the ages of 19 and 52. The participants were split into two groups: one group ate 57 grams of Jarlsberg every day for 6 weeks, and the other group consumed Camembert cheese. The Camembert used in the study contained no vitamin K, whereas the Jarlsberg contained approximately 80 μg of vitamin K and its variants per 100 g of cheese. After the initial 6-week period, the Camembert consumers also switched to Jarlsberg for another 6-week span. (TINE SA, a Norwegian dairy product cooperative, provided all the cheese used for the trial and also funded the study). The participants were asked to avoid other cheese for the duration of the study but otherwise continued with their daily diets and routines.
At the end of each 6-week period, the researchers tested blood samples for vitamin K2 and its variants, osteocalcin, a protein named PINP that’s thought to be one of the best biomarkers of bone formation, and certain forms of collagen that indicate bone formation and breakdown. They also measured typical clinical parameters such as cholesterol and blood lipids.
Both groups had slight increases in their levels of serum triglycerides and cholesterol in the first six weeks of participating in the study. The team found higher levels of the PINP protein in the women who ate Jarlsberg. Serum osteocalcin also increased significantly from an average of 21.4 ng/ml to 25.8 ng/ml in the women who ate Jarlsberg daily but not in those who ate Camembert. But after they switched to Jarlsberg for the second half of the study, total serum osteocalcin concentrations rose in this group too . “That’s how we found out this effect is specific to Jarlsberg cheese and not all kinds of cheese,” Lundberg said. “We were very surprised to see these results.”
The data suggest that Jarlsberg has a significant stimulatory effect on serum osteocalcin, according to the authors. The work is “probably the first time” a dietary intervention has shown a significant increase in the total osteocalcin concentration in a randomized controlled trial, they wrote in the paper.
The proteins and serum biomarkers used in this study serve as proxies to gauge bone health, because it requires approximately a year for changes in bone mass and density to become noticeable. Thus, longer-running studies are needed to confirm whether eating Jarlsberg cheese also affects bone structure in humans. These studies could be conducted in people with borderline, untreated osteoporosis, the authors suggest.
But the increase in osteocalcin isn’t only due to the vitamin K2 present in Jarlsberg, they add. This cheese also contains a compound named 1,4-dihydroxy-2-naphthoic acid (DHNA), formed by propionic acid bacteria in the process of synthesizing vitamin K2. In studies of mice with ovaries removed, researchers have found that vitamin K2 could not stimulate osteocalcin production but DHNA could do so . As a result, the authors of this study suggest that “DHNA is the possible key to the total osteocalcin stimulatory effect of Jarlsberg.” If future studies confirm this effect, the molecule could yield possible new therapies for osteoporosis and to improve bone health.
- Lundberg HE, Holand T, Holo H, Larsen S. Increased serum osteocalcin levels and vitamin K status by daily cheese intake. International Journal of Clinical Trials. 2020 May;7(2):55-65.
- Lundberg HE, Glasø M, Chhura R, Shukla AA, Austlid T, Sarwar Z, Hovland K, Iqbal S, Fagertun HE, Holo H, Larsen SE. Effect on bone anabolic markers of daily cheese intake with and without vitamin K2: a randomised clinical trial. BMJ Nutrition, Prevention & Health. 2022 Jun 30:e000424.
- Kita K, Yamachika E, Matsubara M, Tsujigiwa H, Ishida N, Moritani N, Matsumura T, Mizutani M, Fujita Y, Takabatake K, Ejima K. Anti-osteoporosis effects of 1, 4-dihydroxy-2-naphthoic acid in ovariectomized mice with increasing of bone density. Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 2016 Jan 1;28(1):66-72.