Not even close, especially when it comes to vitamins, nutrients and minerals. For example, take turmeric which is praised for its anti-inflammatory and anti-oxidant benefits...we will usually not readily absorb the active ingredients unless taken together with black pepper.
Black pepper will also improve nutrient availability in general, because it helps digestive enzyme secretion.
Another example is iron, which generally we readily absorb from meat but not plants, however, consuming iron rich plants together with vitamin c improves our iron absorption up to 6x.