Two Types of Vitamin K

Friends who have paid attention to Vitamin K supplements know that many Vitamin K supplements on the market specifically indicate they are Vitamin K2.

If there's a 2, there must be a 1. What's the difference? Is 2 better than 1?

Vitamin K is a fat-soluble vitamin, and there are indeed two natural types: Vitamin K1 and Vitamin K2.

However, Vitamin K1 and Vitamin K2 simply have different primary functions; it's not accurate to say one is better than the other.

As a dietary supplement or health food, people are more concerned with Vitamin K's bone health benefits, which is why most supplements sold are Vitamin K2.

Health Benefits of Vitamin K

Nighttime Leg Cramps

Approximately 50%-60% of adults will experience nighttime leg cramps in their lifetime. A recent study found that daily intake of 180μg Vitamin K2 can significantly reduce the frequency of nighttime leg cramps in the elderly.

Bone Health

Vitamin K is crucial for bone health, participating in making proteins needed for bones. Studies show that higher Vitamin K intake is associated with lower incidence of hip fractures and low bone density.

Blood Clotting

The "prothrombin" responsible for blood clotting is a Vitamin K-dependent protein. When Vitamin K is lacking, it cannot function properly, potentially leading to clotting difficulties.

 

Cardiovascular Health

Studies have found that moderate to high doses of Vitamin K1 intake are associated with reduced risk of all-cause mortality, cardiovascular disease, and cancer-related mortality.

 

Are You Deficient in Vitamin K?

As mentioned earlier, Vitamin K deficiency is not common in healthy adults.

This is because Vitamin K1 is widely found in various green vegetables, and intestinal bacteria also participate in synthesizing Vitamin K2. Vitamin K2 can also be obtained from fermented foods, meat, and dairy products.

Adult Vitamin K deficiency is often secondary to gastrointestinal diseases or medication treatments. However, for children, the situation is somewhat different. Vitamin K deficiency is still relatively common in children.

A study in Shenyang measured serum Vitamin K2 levels in 1732 children aged 0-14 and found that the Vitamin K2 deficiency rate was as high as 52.31%. Studies in Beijing and Anhui also found that Vitamin K2 deficiency rates among children aged 0-14 were generally high, both exceeding 50%.

Daily Requirements & Safety

The appropriate daily intake of Vitamin K for adults over 18 is 80µg. There is no increase during pregnancy based on this, and only increases to 85µg during lactation.

Every 100g of dark green vegetables contains anywhere from tens to hundreds of micrograms of Vitamin K1. For example, spinach's Vitamin K1 content reaches 482.9µg/100g.

Even with some losses during cooking and absorption, eating half a kilogram of vegetables daily is enough to meet the Vitamin K requirement.

Under normal circumstances, a balanced diet usually provides sufficient Vitamin K. But if you truly don't eat enough leafy greens, calcium tablets or Vitamin D that contain Vitamin K can serve as a supplement.

Dietary Vitamin K - Adequate Intake [μg/d]

* indicates the additional requirement based on the adult female requirement of the corresponding age stage.

Data Source: Chinese Nutrition Society, Chinese DRIs (2023)[M]. People's Medical Publishing House, 2023.

Regarding safety, Vitamin K normally metabolizes very quickly in the human body and does not cause the common toxicity issues associated with fat-soluble vitamins. There have been no reports of adverse effects from excessive Vitamin K intake in humans.