A famous health program invited "old experts" to recommend "self-made egg shell powder to supplement calcium" to the audience. The method is: bake the eggshell with low fire, then pound it into eggshell powder in a mortar and add it to steamed bread or rice to eat.
There are two extremes in people's views on this practice: one is that "eggs are excellent food, and calcium supplementation with eggshell powder will naturally have a good effect"; The other is "How does the human body absorb inorganic calcium in eggshells?" .
In fact, both of these ideas are wrong.
Eggshells can really supplement calcium.
The main component of eggshell is calcium carbonate.
Calcium tablets sold in the market are mainly calcium carbonate and calcium citrate, in addition to calcium lactate, calcium gluconate, calcium phosphate, etc., and "liquid calcium" dispersed in water. These different forms of calcium are also the basis for manufacturers to fight price wars with "source" and "absorption rate" as selling points. Among them, calcium carbonate and calcium tablets are the most popular, and their prices are also low, which is not emphasized by manufacturers. Other "high-grade products" often target it, accusing it of "inorganic calcium", "low absorption rate" and "constipation" and so on.
Thus, the stereotype of "calcium carbonate tablets are not good" has been formed among consumers.
However, the National Institutes of Health (NIH) reports that when these different forms of calcium preparations are eaten with food, the efficiency of calcium absorption by human body is similar. This is because food causes gastric acid secretion and releases calcium from the preparation. Food slows down the speed of calcium passing through the gastrointestinal tract, thus having more time to absorb it. Calcium citrate is special, it is not affected by gastric acid secretion.
In other words, if the gastric acid secretion is normal, or if you eat calcium tablets with food, whether you eat "cheap and sufficient" calcium carbonate tablets or other "high-grade calcium tablets" are similar.
Egg shell powder is not more effective than the cheapest calcium tablets.
In short, grinding eggshells into powder can really supplement calcium.
However, this powder is still calcium carbonate, not because it turns around in the chicken's body and will have a better calcium supplement effect.
In this project, eggshells are dried and ground with mortar. In fact, it is difficult to grind into very fine powder. Whether it is put in steamed bread or rice, it will greatly affect the taste.
It tastes bad and has no better effect. Why bother?
The waste utilization of egg shells is an industry problem.
The weight of eggshells accounts for about 12% of the weight of eggs. In modern food industry, a large number of eggs are concentrated and processed into egg liquid and egg powder for reuse. Small eggs are processed into thousands of tons of eggs every year, and large processing plants process tens of thousands or even hundreds of thousands of tons of eggs. These processing plants produce hundreds to thousands of tons of eggshells every year.
There is some egg liquid left on the eggshell, which will soon stink when piled together. For these egg processing plants, eggshells are not only unsalable, but also expensive to dispose of.
Theoretically, they can be used to supplement calcium. In the current industry, they can also be ground into powder and used as animal feed. However, cleaning, disinfection and processing into powder also require costs. Compared with calcium carbonate powder produced by other ways, feed manufacturers will not use it if it is not cheaper.
It is also possible to give people calcium supplements, but it is indeed allowed abroad. However, just like the problems faced by feed additives, there is no cost advantage in using egg shells as calcium supplement products. After all, it's just calcium carbonate. There are already very economical and mature processes for producing calcium carbonate in other ways. Unless "egg calcium supplement" is used as a gimmick to fool consumers, there is no advantage in participating in market competition.
More importantly, eggshells are not traditional food raw materials. To use it to produce calcium supplements, we must first declare "new resource food" and get approval. A few years ago, a company in Beijing developed a production line to make egg shell powder, hoping to sell it as a "calcium supplement". Because eggshells have not been approved as food raw materials so far, they can only be in the "experimental stage" and cannot be produced and sold.