Fish intake, independent of apo(a) size, accounts for lower plasma lipoprotein(a) levels in Bantu fishermen of Tanzania - The Lugalawa study

Plasma lipoprotein(a) [Lp(a)] levels are largely genetically determined by sequences linked to the gene encoding apolipoprotein(a) [apo(a)], the disti nct protein component of Lp(a). Apo(a) is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 dom ain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. In 2 racially homogeneous Bantu populations from Tanzania differing in thei r dietary habits, we found that median plasma levels of Lp(a) were 48% lowe r:in those living on a fish diet than in those living on a vegetarian diet. Considering the relationship between apo(a) size and Lp(a) plasma concentr ation, we have extensively evaluated apo(a) isoform distribution in the 2 p opulations to determine the impact of apo(a) size in the determination of L p(a) values. The majority of individuals (82% of the fishermen and 80% of t he vegetarians) had 2 expressed apo(a) alleles. Additionally, the fishermen had a high frequency of large apo(a) isoforms, whereas a higher frequency of small isoforms was found in the vegetarians. When subjects from the 2 gr oups were matched for apo(a) phenotype, the median Lp(a) value was 40% lowe r in Bantus on the fish diet than in those on the vegetarian diet. A signif icant inverse relationship was also found between plasma n-3 polyunsaturate d fatty acids and Lp(a) levels (r= -0.24, P=0.01), The results of this stud y are consistent with the concept that a diet rich in n-3 polyunsaturated f atty acids, and not genetic differences, is; responsible for the lower plas ma levels of Lp(a) in the fish-eating Bantus and strongly suggest that a su stained fish-based diet is able to lower plasma levels of Lp(a).