Cod liver oil is a popular supplement with older people, as it has been found to keep joints healthy and supple, and these are important benefits if you want to keep your body feeling young and active. Cod liver oil is also a rich source of EPA (eicosapentoenoic acid) and DHA (docosahexaeonic acid) It has been shown that cod liver oil can improve the texture of skin, hair and nails. Not suitable for vegetarians or vegans.