Beans, greens and dairy may have been kitchen staples for decades, bdeviut now those humble, whole products are in fashion with beauty investors, who see flavorful, nutrient-dense foods, shakes and drinks as the new wave in wellness . Deals for products that fuse food , wellness and an inside-out approach to beauty have been multiplying, with a flurry of investment activity in the past month alone.   Unilever agreed to purchase Grüns, which sells gummy supplements filled with fruits, vegetables and prebiotic fiber, for an estimated $1.2 billion, while Iris Ventures led a multimillion-dollar round investment in Lucille Health.…