Vegans, or vegetarians who consume no animal products of any kind, may be at an increased risk of blood clots and hardened arteries, mainly due to certain nutrient deficiencies.

A lack of of omega-3 fatty acids and vitamin B12 was was found to have a particularly close association with the risk of atherosclerosis, according to a metastudy published in the Journal of Agricultural and Food Chemistry.

The authors qualified this statement by saying that meat eaters have a much higher total risk of heart disease, but that the above lack of nutrients still carries a moderate risk.

Researchers analyzed data from 30 years’ worth of articles on the nutritive health of vegetarians. They discovered that vegetarians who abstain from all animal-derived products, including milk, cheese and eggs, tended to have low levels of iron, zinc, omega-3s and vitamin B12.

While the human body can extract iron and zinc from fresh fruits, vegetables and whole grains, the latter two nutrients are found almost exclusively in meat, seafood and eggs. Omega-3 and vitamin B12 deficiencies can predispose an individual to arterial hardening and blood clots.

The study’s authors concluded that vegans and strict vegetarians may consider taking vitamin supplements that contain these nutrients, such as those derived from fish oil or nuts.