Healthier is comparative of healthy.
Health is not an adjective and therefore does not have comparative and superlative forms.Healthy, however, is an adjective, with the comparative form of healthier and the superlative form of healthiest.
healthier, more healthy
healthier
healthier
healthier
healthier, healthiest
healthier
healthier, healthiest
healthier, healthiest
healthier, healthiest
heathy