Either natural or synthetic substances may be added to avoid or delay these problems. Fortification adds a nutrient that wasn't there before and may be lacking in many people's diets. Iodized salt is an example. This has proven useful in preventing goiter, a thyroid disease caused by a deficiency in iodine. Enriched and fortified foods are labeled as such.
Preservatives are centuries old.
Since ancient times, salt has been used to cure meats and fish, and sugar has been added to fruits to conserve them. Herbs, spices, and vinegar have also served as preservatives. Granted, mistakes have been made, which have resulted in taking some food additives and preservatives off the market. That is because at the time of approval, prevailing testing methods proved the substances as safe. As science continued to evolve and testing methods improved, changes were made.