There are numerous unsubstantiated reports that natural vitamins are superior to synthetic ones，that fertilized eggs are nutritionally superior to unfertilized eggs，that untreated grains are better than fumigated grains and the like.

(并列同位语从句reports that…，that…，that…)

关于天然维生素优于人造维生素，受精蛋比未受精蛋的营养价值更高，未经熏蒸消毒处理的谷物比经过处理的好等等报道屡见不鲜，但都没有得到证实。

分句1：There are numerous unsubstantiated reports

分句2：that natural vitamins are superior to synthetic ones

分句3：that fertilized eggs are nutritionally superior to unfertilized eggs

分句4：that untreated grains are better than fumigated grains and the like

分句1是整个长句的主句，分句2、分句3和分句4是并列关系，共同构成分句1的同位语从句。本句的意思是有很多没有经过证实的报道，然后并列了三个未经过证实的报道的从句。