According to Dr Norman Pollock, bone biologist at the Georgia Prevention Institute at the Medical College of Georgia at Augusta University, supplementation with vitamin K may be an effective, inexpensive way to help reduce the cardiovascular risk of obese children.
"It's an obscure vitamin that most of us probably don't get enough of," Pollock said. "We hope it will be a safe alternative for these children and potentially others to ensure their cardiovascular health."
Pediatric vitamin K trial: Study Design
For eight weeks, researchers will intervene the diets of 60 obese children aged 8 to 17, randomly allocated to either a control group receiving placebo, the low-dose vitamin K2 (menaquinone-7) group (45 mcg per day), or the high-dose group (90 mcg per day).
To be included in the study, children should have higher fasting glucose levels, a sign of an already increased diabetes risk. The intervention’s outcome will be measured by looking at markers of cardiovascular health such as blood levels of triglycerides, good and bad cholesterol, as well as insulin production and sensitivity.
“The central hypothesis is that vitamin K-induced carboxylation of matrix GLA protein and osteocalcin will influence markers of dyslipidemia and diabetes risk, respectively,” a summary of the study proposal said. “The potential beneficial effects of vitamin K-dependent proteins on lipid and glucose metabolism is innovative and makes for a suitable area of investigation in a pediatric population at risk of developing atherosclerotic cardiovascular disease in adulthood.”
Because osteocalcin, which can increase insulin production by the pancreas and insulin sensitivity, cannot be supplemented directly to humans, Pollock wondered if vitamin K would yield the same cardiovascular benefit. "We need vitamin K to make osteocalcin active," Pollock said. "We think it all ties together."
Fighting childhood obesity in the US
"We want to know who benefits most from vitamin K supplementation," Pollock added. The new studies include giving a high and lower dose of vitamin K, and Pollock notes that his preliminary studies have indicated a dose-response effect.
The US is notorious for being an industrialized country with one of the worst track records for health, a trend experts call “overfed and undernourished.” Efforts to fight childhood obesity and its related risks are coming from multiple channels. After last week’s presidential election, four more US cities have voted to levy a tax on sugary drinks.
In the nutritional supplement space, experts such as the Council for Responsible Nutrition’s (CRN) Duffy MacKay advocate dietary supplements as a short-term solution. “I say short-term because everyone’s vision should be a population that gets all the nutrients they need from their diet, that should be the goal,” he told NutraIngredients-USA in a past interview. “Right now, we are so far from reaching that goal, and we need to be pragmatic.”
K forms
There are two main forms of vitamin K: phylloquinone (vitamin K1), which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10% of Western vitamin K consumption and can be synthesized in the gut by microflora.
Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.
The potential health benefits of the vitamin include cardiovascular and bone health, with some data also supporting a role for prostate health and cognitive benefits.