The invention relates to a nutritional supplement comprising: a) from 9 to 17 wt. % of Spirulina maxima alga; b) from 20 to 40 wt. % of concentrated whey protein; c) from 10 to 40 wt. % of isolated soy protein; y d) from 20 to 40 wt. % of coconut powder. The pharmaceutical form of said nutritional supplement is a powder for reconstitution, a solution, a suspension, an emulsion, capsules, tablets, flakes or fruit-enriched bars, and can be used to improve the nutritional state of people who suffer from rheumatic diseases.