By Erin Kelley, MS, RD
In the fashion world, trends come and go, and the dietary supplement industry shares the same “what’s hot” and “what’s not” faddism. For the last three years, vitamin D has soaked up the spotlight. The nutrient gained attention from an increasing number of research studies showing benefit to a myriad of diseases—cancer, autoimmune disorders, immune health, depression, and last but not least, death. But like bell bottom pants, vitamin D’s staying power may be short-lived. Word on the street is that vitamin K is the new D.
It started with a cluster of research done on vitamin K in the early 2000s. A 2003 study in the American Journal of Clinical Nutritionfound low dietary intake of vitamin K was associated with low bone mineral density in women, which validated similar outcomes in other studies and associations between low vitamin K intake and a higher risk of hip fracture. A year later, the same journal published a study showing girls with a better vitamin K status had better bone turnover. But bone health wasn’t the only association researchers noticed. Over the next few years, studies on vitamin K would show associations between high vitamin K status and reduced risk of prostate, lung, and liver cancers, and protection against coronary heart disease.
Two forms of vitamin K exist: vitamin K1 (phylloquinone) is found in leafy green vegetables. Vitamin K2 (menaquinone) is synthesized by bacteria and is found in fermented soybeans and certain cheeses. Much of the research done has looked at vitamin K2. Both forms are essential for the proteins involved in blood clotting and are necessary for proteins that are needed to form bone. Although vitamin K is fat-soluble, the body does not store much and it can be depleted without regular dietary intake. However, it may be difficult to get in the daily diet.
If you are starting to think vitamin K sounds a lot like vitamin D’s recent milieu, you’re right. While more research is needed (isn’t that always the case?), expect to hear more about vitamin K in both research and product developments.
UPDATE: 27 APRIL 2010 - Mayo study links increased vitamin K intake to lower non-Hodgkin lymphoma risk
A higher intake of vitamin K is associated with a reduced risk of non-Hodgkin's lymphoma, an immune system cancer that is the most common blood malignancy in the United States.
In research funded by the National Cancer Institute, cancer epidemiologist James Cerhan, MD, PhD and his colleagues at the Mayo Comprehensive Cancer Center compared 603 newly diagnosed non-Hodgkin lymphoma patients to 1,007 men and women who did not have cancer. Dietary questionnaire responses were analyzed for vitamin K intake from food and supplements.
The investigators found an association between a lower risk of non-Hodgkin lymphoma and increased consumption of vitamin K. For those whose intake of the vitamin was among the top 25 percent of participants at over 108 micrograms per day, the risk of the disease was 45 percent lower than those whose intake was among the lowest fourth at less than 39 micrograms per day. Adjustment of the analysis for age and other factors failed to modify the association. When vitamin K from supplements was examined, intake of the vitamin was also shown to be protective up to a certain level, above which increased intake offered no additional benefit, suggesting that it is not necessary to supplement with high doses for protection to occur.
Vitamin K is well known for its role in blood coagulation; however, an ability of the vitamin to inhibit inflammatory cytokines and involvement in cell cycle arrest and cell death pathways could help explain the benefit suggested by the current study's outcome.
"Whether the protective effect we observed is due to vitamin K intake, or some other dietary or lifestyle exposure, cannot be definitely assessed in this study," Dr Cerhan remarked. "But these findings add to a lot of other data that support a diet that includes plenty of green leafy vegetables in order to prevent many cancers as well as other diseases."
"These results are provocative, since they are the first work we have done on the connection between vitamin K and Non-Hodgkin lymphoma, and this is a fairly strong protective effect," he noted. "However, as with all new findings, this will need to be replicated in other studies."
I am a great fan of tomatoes and also vitamin K supplying foods. What makes it more supportive of my long held views are two new reports I received today.
I have posted on the benefits of vitamin K for osteoporosis in the past, and now we have more data on its benefit in cancer.
An article published online on March 24, 2010 in the American Journal of Clinical Nutrition reports the finding of researchers from the German Cancer Research Center and the German Research Centre for Environmental Health of an association between reduced vitamin K2 intake and an increased risk of dying from cancer.
The current research analyzed data from 24.340 participants in the European Prospective Investigation into Cancer and Nutrition-Heidelberg (EPIC-Heidelberg) prospective study who were aged 35 to 64 upon enrollment between 1994 and 1998. Participants, who were free of cancer at the beginning of the study, were followed through 2008. Dietary questionnaires completed upon enrollment were analyzed for phylloquinone (vitamin K1) and menaquinones (vitamin K2) intake.
Over the follow up period, there were 1,755 cases of cancer, including 458 fatalities. While the those whose intake of vitamin K2 was among the top 25 percent of participants had a 14 percent nonsignficant reduction in cancer incidence compared with those whose intake was among the lowest fourth, the group with the highest intake experienced a 28 percent lower risk of dying of the disease. Further analysis of the data determined that the reduction in cancer incidence associated with vitamin K2 occurred in men. When cancers were examined by cause, a 62 percent reduction in the risk of lung cancer and a 35 percent lower risk of prostate cancer were observed in those whose intake of vitamin K2 was among the top 25 percent. Although exclusion of prostate and lung cancer from the analysis still found an inverse association between vitamin K2 intake and metastatic cancer risk, the researchers did not consider it to be of statistical significance. No associations were found between vitamin K1 and cancer incidence or mortality.
The authors explain the difference in vitamin K2's effects on men and women by the fact that the men in the study had cancer sites (prostate, lung) that were likelier to be influenced by vitamin K2. Concerning the greater inverse association of vitamin K2 with cancer mortality compared to cancer incidence, the authors remark that "This observation is consistent with the assumption that factors affecting apoptosis and cell cycle arrest are likely to play a role later in carcinogenesis. In addition, experimental studies suggest an inhibitory role of menaquinones in angiogenesis, which is tightly linked to the development of metastasis."
"This study showed inverse associations between the dietary intake of menaquinones and both overall cancer incidence and mortality," the authors conclude. They suggest additional studies using biomarker measurements of vitamin K status.
and
"Dietary vitamin K intake in relation to cancer incidence and mortality: results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)," Nimptsch K, Rohrmann S, et al, Am J Clin Nutr, 2010 March 24; [Epub ahead of print]. (Address: J Linseisen, Institute of Epidemiology, Helmholtz Zentrum Munchen, German Research Centre for Environmental Health, Ingolstadter Landstr. 1, D-85746 Neuherberg, Germany. E-mail: j.linseisen@helmholtz-muenchen.de ).
Summary: In a prospective cohort study (EPIC-Heidelberg) involving 24,340 subjects between the ages of 35 and 64 years, free of cancer at enrollment, followed up with for an average of > 10 years, during which time 1,755 incident cases of cancer occurred of which 458 were fatal, dietary intake of menaquinones (vitamin K2) was found to be inversely associated with overall incidence of cancer (for highest vs. lowest quartile HR=0.86), and cancer mortality (HR=0.72). The reduction in risk associated with increasing intake of menaquinones was even greater in men than in women, specifically seen with prostate and lung cancers. No association was found for phylloquinone (vitamin K1) intake. The authors conclude, "These findings suggest that dietary intake of menaquinones, which is highly determined by the consumption of cheese, is associated with a reduced risk of incident and fatal cancer."
Lycopene now shows help in glioma, which again should be considered for its high antioxidant capacity -
"Lycopene in treatment of high-grade gliomas: A pilot study," Puri T, Goyal S, et al, Neurol India, 2010 Jan-Feb; 58(1): 20-3. (Address: Department of Radiation Oncology, All India Institute of Medical Sciences, New Delhi - 110 029, India).
Summary:In a randomized, placebo-controlled study involving 50 patients with high-grade gliomas treated with surgery followed by adjuvant radiotherapy and concomitant paclitaxel, oral supplementation with lycopene (8 mg/d) along with radiotherapy was found to exert potentially beneficial effects. Specifically, prior to supplementation, lycopene levels were 152 ng/ml and after supplementation 316 ng/ml, as compared to no significant change found in the placebo group. More favorable overall response at 6 months, last follow-up, and time to progression (40.83 vs. 26.74 weeks) were found in the lycopene group, as compared to the placebo group, though the differences were considered non-significant. Follow-up duration was significantly higher among those taking lycopene (66.29 weeks), as compared to placebo (38.71 weeks). The authors conclude, "Addition of nutrition supplements such as lycopene may have potential therapeutic benefit in the adjuvant management of high-grade glioma s."
So you see there is a clear pattern for the need of supplementation in prevention and treatment of cancers, along with powerful and good nutrition - against what you may hear and read in mainstream media or from your doctor (or the doctor who tells you not to eat broccoli because it interferes with chemo).