Recent interest in vitamin K2 has led advocates of grass-fed beef to focus on its vitamin K2 content (J of Agriculture and Food Chemistry, 2006;25;54(2):463-7). Sellers of cow's meat either let their cows eat grass, or they can make the cows fatter and produce more meat by feeding them corn. The latest argument for eating meat from grass-fed cows is that grass is full of vitamin K1. Animals that graze on grass can convert the vitamin K1 in grass into vitamin K2 and it accumulates in their muscles, so when you eat meat from grass-fed cows, you gain the health benefits of vitamin K2 (listed below). Vitamin K2 is soluble in fat so it can also be found in other fatty foods such as eggs and fatty dairy products. Fermented foods are also good sources of vitamin K2.

Most leafy-green vegetables are loaded with K1, so when you eat plants that contain vitamin K1, bacteria in your intestines can convert K1 into K2 and you absorb K2 into your bloodstream. K2 appears to be significantly more effective than K1 in helping to prevent and treat osteoporosis, atherosclerosis, heart attacks, cancers, and inflammatory diseases (Int J Mol Sci, 2019;20:896).

Health Benefits of Vitamin K2
Beneficial functions of vitamin K2 include:
• Directing calcium to deposit into bones to help prevent osteoporosis, a disease that affects 200 million people worldwide, and causes one in three women over 50 and one in five men to suffer from osteoporotic broken bones (Eur J Rheumatol, 2017 Mar;4(1):46-56).
• Directing calcium to be deposited in teeth to help prevent dental cavities.
• Reducing calcium deposition in arteries to help prevent plaques from forming in arteries (Nutrients, Feb 2021;13(2):691) and increasing heart attack risks (Cureus, 2016 Aug 24;8(8):e748). Taking in at least 32 micrograms of K2/day has been associated with reduced calcification of blood vessels and heart attack risk by 50 percent (J Nutr, 2004 Nov;134(11):3100-5).
• Reducing calcium deposition in kidneys to help prevent kidney damage.
• Having both anti-oxidant and anti-inflammatory effects to help prevent tissue damage that can increase risk for dementia.
• Helpng to lower high blood sugar levels by increasing insulin sensitivity

Other Possible Health Benefits of Grass-Fed Beef
The health benefits of eating grass-fed rather than corn-fed beef are very controversial (Meat Science, January 2014; 96(1):535-540; J of Agriculture and Food Chemistry, 2006;25;54(2):463-7). In addition to its vitamin K2 content, the main health arguments for eating grass-fed meat are its lower total and saturated fat content, and its higher omega-3 fatty acid content (Meat Science, January 2014; 96(1):535-540).
• There is no evidence that the small reduction in fat from eating meat from grass-fed cows, rather than corn-fed cows, offers any real health advantage. It’s the total fat in a diet, not just the fat in meat, that determines blood test results that check on blood levels of the heart-attack-predicting elevated LDL cholesterol and triglycerides. Reducing dietary fat sometimes lowers LDL, but often raises triglycerides.
• Grass-fed beef contains two to six times more omega-3 fatty acids than feed-lot beef. Omega-3 fatty acids have been found to help prevent and treat many diseases. They include heart disease, stroke, autoimmune diseases such as lupus, eczema, rheumatoid arthritis, and others. However, grass-fed beef contains far fewer omega-3s than fatty fish, nuts or seeds.
• Grass-fed beef contains more antioxidants than grain-fed beef, and antioxidants help to prevent cell damage that can lead to serious diseases such as cancer and Alzheimer's disease.
• While it still contains saturated fat, grass-fed beef has somewhat lower levels of saturated fats, total fats and cholesterol than corn-fed beef (Food Sci Anim Resour, 2022 Jan; 42(1): 18–33).
• Most people prefer the flavor of corn-fed meat (Nutr J, 2010;9:10) because an increased amount of fat is usually what makes meat taste good and corn fed meat has more fat (Journal of Dairy Science, 97 :1828–1834). Grass-fed meat is usually more expensive, since it takes more land to feed the cows only grass and it takes longer for cows to reach market weight. However, heavy advertising to persuade people that grass-fed meat is more healthful can also influence their taste preferences (Int J of Hosp Man, September 2014;42:137–143) and their willingness to pay higher prices.

Health Risks from Beef and Other Mammal Meats
Whether it's grass-fed or grain-fed, all beef has some potential health risks. See Red Meat Associated with Increased Risk for Diabetes
Eating Mammal Meat is Associated with Increased Risk for Gastro-Intestinal Cancers
How Eating Meat Increases Risk for Heart Failure

My Recommendations
You will not prevent heart attacks or diabetes by choosing meat from grass-fed cattle. I believe that a healthful diet is low in meats from mammals (fresh or processed), regardless of their food source or their fat content. If you want to eat more omega-3 fatty acids, eat fish and a variety of nuts and seeds. If you want to eat vitamin K2 in food sources rather than supplements, eat more leafy greens and let your colon bacteria convert the K1 to K2. The recent articles on the health benefits of vitamin K2 should encourage you to eat a plant-based diet, rather than meat from grass-eating cattle.