Summary:

Weston A. Price identified a powerful, fat-soluble nutrient—now believed to be similar to vitamin D—that he called "Activator X." He proposed that modern diets lack a key nutritional factor, which could explain why traditional populations had strong bones and were largely free of tooth decay. This nutrient, Activator X, is found most abundantly in dairy products from grass-fed animals, especially when they graze on fast-growing green pasture. It also appears in fish eggs, and in the organs and fat of land animals that feed on rapidly growing plants.

Price speculated that Activator X may originate from plant compounds produced during vigorous growth, which are then converted by grazing animals into a substance that helps rebuild and protect teeth. Based on personal experience, author Ramiel Nagel emphasized that consuming grass-fed butter is crucial for reversing tooth decay. The nutrient content in butter can often be gauged by its color—rich yellow or orange shades suggest a higher concentration of vital compounds like Activator X. However, the presence of this nutrient depends on several factors, including the season, soil quality, animal breed, and the specific grasses and herbs consumed. Butter only becomes a potent source of Activator X when animals graze during times of rapid pasture growth, typically from late spring through early fall.

From Cure Tooth Decay, Ramiel Nagel, p. 73.

In 1942, Hereford, Texas earned the nickname “Town without a Toothache” due to Dr. George Heard’s discovery that residents had remarkably low rates of tooth decay. He attributed this to the regular consumption of raw, grass-fed milk and fermented dairy products like buttermilk, clabber, and yogurt. Heard observed that individuals who drank a quart of this nutrient-rich milk daily—especially from cows grazing on mineral-rich native grass—developed resistance to cavities. The milk provided essential minerals (calcium, phosphorus), fat-soluble vitamins (A, D, C), and beneficial probiotics. Soured milk products, naturally fermented before refrigeration existed, aided digestion and nutrient absorption, further promoting dental and overall health.

From Cure Tooth Decay, Ramiel Nagel, p.86, citing

Heard, George W. "Chapter 17." Man versus Toothache. Milwaukee: Lee Foundation for Nutritional Research, 1952. Print. https://www.amazon.com/Man-vs-Toothache-George-Heard/dp/B00545T0CK/ref=sr_1_1