Animal protein has more of a specific amino acid named methionine than vegetable protein does. Methionine has come under intensified scrutiny lately due to some studies that suggest that excess methionine reduces lifespan. Aside from that body of research, it has been shown that excess methionine causes blood to become more acidic. When this happens, the sulfur from the methionine combines with exchangeable calcium from the bones to create calcium sulfate which is then expelled from the blood and excreted from the body, thus reducing the body acidity. If our body acidity is constantly elevated from daily consumption of dairy, our bones will constantly leach calcium in a struggle to lower that acidity.
Now, if this were true, shouldn’t populations that eat large amounts of dairy on a daily basis have weaker bones? In fact, they do as evidenced by a study that considers total animal protein. There was a large scale study of animal protein consumption vs bone strength from different populations around the world. This study showed that the more animal protein a population eats, the more likely that population is to have weaker bones, as measured by hip fractures. It should be noted that this study, though large scale, focused on women; the jury is still out for men.
So, if there is indeed a link between calcium, methionine, and strong bones, then the calcium/methionine ratio, though maybe not direct, could shed some light on the subject. The following lists vegetables that are highest in calcium, vegetables highest in methionine, soymilk, and dairy.
| Food | Methionine (mg/Cal) | Calcium (mg/Cal) | Calcium/ Methionine | Comment |
| Soymilk, fortified | 0.37 | 2.85 | 7.7 | |
| Watercress | 1.82 | 10.2 | 5.6 | Highest in Calcium & High in Methionine |
| Turnip Greens | 1.06 | 5.83 | 5.5 | High in Calcium |
| Kale | 0.64 | 2.74 | 4.28 | High in Calcium |
| Mustard Greens | 0.96 | 3.85 | 4.01 | High in Calcium |
| Spinach | 2.31 | 4.24 | 1.84 | Highest in Methionine & High in Calcium |
| Milk, nonfat | 2.46 | 3.69 | 1.5 | |
| Soybean | 1.23 | 1.34 | 1.09 | High in Methionine |
| Asparagus | 1.55 | 1.19 | 0.77 | High in Methionine |
| Baby Zucchini | 1.86 | 1.13 | 0.61 | High in Methionine |
| Crimini Mushrooms | 1.78 | 0.72 | 0.4 | High in Methionine |
| Kidney Bean | 1.16 | 0.43 | 0.37 | High in Methionine |
| Cottage Cheese | 5.18 | 0.85 | 0.16 |
The type of soymilk that I chose is fortified with calcium since it is the most common way to buy soymilk in the US. Notice that the vegetable highest in methionine, spinach, contains 2.31 mg/Cal whereas cottage cheese, like most cheese, is twice as high with 5.18 mg/Cal. On the other hand, the vegetable highest in calcium, watercress, has 10.2 mg/Cal of calcium and milk has 3.69 mg/Cal. It would appear that simply replacing milk with soymilk in our breakfast cereal would reduce our methionine levels and increase the calcium density, calcium stores in our bones. Moreover, if we stick to the vegetables for the rest of the day instead of that hamburger and milkshake, then we will be much less likely later in life to cry, “I’ve fallen, and can’t get up!”
