By Lucina E. Lampila*
High circulating cholesterol in humans was correlated to heart disease and the risk of heart attack or stroke. This resulted from correlations made from a study that began in 1949 of over 5,000 men and women in Framingham, Massachusetts, a suburb of Boston. An early publication in the American Heart Journal (1951) from this study reported on the importance of a reduced fat and cholesterol diet to reduce morbidity and mortality rates in patients with coronary atherosclerosis. Recommendations soon followed from the American Heart Association with dietary restrictions on high fat foods (some of which also contain appreciable cholesterol), such as, highly marbled meats, organ meats, sardines, avocados, olives, fish canned in olive oil, and foods high in cholesterol: eggs, shrimp, crab, lobster and clams, to name a few. Polyunsaturated fatty acids were recommended and patients were told to avoid butter in favor of oleomargarine and polyunsaturated, vegetable oils. Dietary cholesterol intake was recommended to be less than 300 mg per day.
As with many dietary recommendations, subsequent studies have been conducted with new conclusions that appear contrary to standing dietary indications. Studies with marine oils showed that fatty fish containing high levels of the omega-3 fatty acids (Copper River Salmon, sardines and mackerel) were shown to elevate high density lipoproteins (HDL or the ‘good cholesterol’), reduce low density lipoproteins (LDL or the ‘bad cholesterol’) and reduce the biochemical markers of inflammation. Studies with the Mediterranean diet showed that the monounsaturated fatty acids from sources such as olive oil and avocados also favorably altered circulating cholesterol types and markers of inflammation. Further studies involving eggs in the adult diet vindicated the egg as a culprit in elevating serum cholesterol.
Recently, the Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC) was submitted to the Secretaries of the Departments of Health and Human Services (HHS) and the United States Department of Agriculture (USDA). Every five years, the committee meets to evaluate the most current research on topics related to diet, nutrition and health. Information and recommendations in the report may be used by the HHS and USDA when developing the Dietary Guidelines for Americans later this year.
The 2010 Dietary Guidelines for Americans (DGA) contained a recommendation that the daily intake of dietary cholesterol not exceed 300 mg. The 2015 DGAC did not renew this recommendation because cholesterol is not a nutrient of concern for over consumption. This was in agreement with the conclusions reported in the 2013 American Heart Association and American College of Cardiology Task Force on Practice Guidelines that there is not a substantial relationship between consumption of dietary cholesterol and serum cholesterol. The draft guidance also includes limiting consumption of saturated fat to less than 10% of total calories and limit trans fat.
The DGAC also recommends eating more seafood be it wild or aquacultured. The advantages of seafood consumption outweigh the minor risks posed by contamination of methyl mecury or organic pollutants. This is consistent with guidance issued by the United States Food and Drug Administration (FDA) for women who are pregnant or into to become pregnant. Three of the five of the most commonly eaten fish, cited by FDA, that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish are commonly farmed.
The global production of seafood has surpassed that of beef. The DGAC also recognized there is a need to establish strong policy, research, and stewardship to improve the environmental sustainability of farmed seafood systems. Although the DGAC recognized that the levels of the omega-3 fatty acids could be equal or greater in farmed than wild caught seafoods; there is a need to improve and retain the omega-3 profiles of certain species via improved feeding and processing practices.
When issuing the 2015 Dietary Guidelines, the FDA and USDA do not have to adopt all the recommendations issued by the DGAC; the potential to reverse decades of a dietary restriction on some heart healthy seafoods, such as, shrimp, crab, lobster, clams and sardines is important. The public is encouraged to respond the DGAC as described in the Federal Register announcement.
*Lucina E. Lampila, Ph.D., R.D., C.F.S. is a food scientist who has worked with the U.S. Sea Grant College Program at academic institutions on the West Coast, in the Mid-Atlantic and the Gulf Coast. She worked for ingredient manufacturers in the private sector and had global responsibilities for value-added seafood processing.