This is a blurb from HSI's Healthy e-alerts:
Today I have important information for the 20 million Americans who suffer from osteoarthritis (OA), a chronic form of arthritis that causes painful inflammation of joints and loss of cartilage.
New research indicates that a deficiency of one vitamin may increase the severity of OA.
Boston uncommon
Low levels of vitamin K may trigger abnormalities in bone and cartilage, says Boston University School of Medicine researcher Tuhina Neogi in an interview that appeared in Bostonia (the BU alumni quarterly). Neogi noted this as the impetus behind her examination of vitamin K and osteoarthritis.
Neogi and her team examined data collected from more than 670 subjects who participated in the Framingham Offspring Study. Blood samples revealed levels of phylloquinone (also known as vitamin K1), and x-rays were used to assess joint space narrowing and the presence of osteophytes; the bony growths that sometimes form in the joints of OA patients.
The study produced two key results: 1) Low vitamin K1 levels were associated with a greater severity of OA, and 2) Subjects with lower K1 levels had a greater number of osteophytes than subjects with high levels of the vitamin.
Based on the outcome of this study (published in the current issue of Arthritis and Rheumatism), the BU team has already received Arthritis Foundation funding for a clinical trial in which OA patients will receive either a vitamin K supplement or a placebo.
Neogi told Bostonia: "We don't know how much vitamin K is necessary for these bone and cartilage proteins to function optimally. Our preliminary observational results suggest that we probably need more vitamin K than the recommended daily allowance."
Leafy greens
The current recommended daily allowance for vitamin K is 65 micrograms for women over the age of 25, and 80 micrograms for men in the same age group. But in his Nutrition and Healing newsletter, Jonathan V. Wright, M.D., recommends 5 to 15 MILLIGRAMS per day.
When I asked HSI Panelist Allan Spreen, M.D., about vitamin K, he offered these comments: "The plant-based source of vitamin K1 seems to have no toxic effects in most any reasonable dose. But the synthetic form (K3, or menadione) has caused some liver toxicity and, rarely, a form of anemia when taken in high doses. There's also K2 (or menaquinones), but K1 and K2 are fine. As usual, it seems best to avoid synthetic forms, if possible. If the individual is on coumadin (blood thinner), he needs to talk with his doctor, as vitamin K can interfere with its effect."
As for dietary sources of vitamin K, Dr. Spreen notes that dark, leafy green vegetables, such as kale and carrot tops, are the best for vitamin K1. "The highest amounts of it are in chestnut leaves and fish meal. Spinach leaves, cabbage leaves and cauliflower are also right up there."
In addition to those sources, broccoli, Brussels sprouts, endive, and lettuce are also abundant in vitamin K1, as are olive oil and avocados. Vitamin K1 is converted into K2 in the intestine, but we get some amount of K2 in meat, liver and egg yolk, and fermented products such as yogurt and cheese.
Sources:
"Low Vitamin K Status is Associated with Osteoarthritis in the Hand and Knee" Arthritis and Rheumatism, Vol. 54, No. 4, April 2006, interscience.wiley.com "Is There a Link Between Vitamin K and Osteoarthritis?" Cynthia K. Buccini, Bostonia, Fall 2005, bu.edu
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