iron

In poor parts of the world, people may rely on a single staple crop to meet a substantial proportion of their energy requirements. For example, those who live in southeast Asia rely heavily on rice.
Dietary supplement use, albeit nutritional products or alternative medicines, is a very lucrative industry that is for the most part riddled with overly auspicious claims in support of the notion they are a panacea.
An untreated iron deficiency could lead to various health problems, one being Iron Deficiency Anemia (IDA). Now, researchers have discovered IDA itself could be linked to another potential problem — hearing loss. 
As a greater number of people enter the middle class around the globe, many will turn away from plant-based diets in favor of meat-based diets.