Table 3.

Mean intake of types of protein in US adults aged ≥20 years, stratified by income, National Health and Nutrition Examination Survey 1999–2010, USA

	<1·30†				1·30–<3·50				≥3·50				P-interaction
	1999–2000 (n 1110)		2009–2010 (n 1746)		1999–2000 (n 1405)		2009–2010 (n 1973)		1999–2000 (n 1137)		2009–2010 (n 1509)
	Mean	se	Mean	se	Mean	se	Mean	se	Mean	se	Mean	se
Mean intake (g/kg) and se ‡
Beef	0·66	0·06	0·67	0·03	0·74	0·04	0·66*	0·04	0·66	0·05	0·53	0·03	0·20
Pork	0·35	0·04	0·42	0·03	0·42	0·04	0·37	0·02	0·35	0·03	0·32	0·02	0·14
Lamb or goat	0·01	0·01	0·02	0·001	0·01	0·001	0·02	0·01	0·01	0·01	0·01	0·001	0·04
Chicken	0·44	0·05	0·54**	0·03	0·51	0·04	0·49	0·03	0·46	0·03	0·53**	0·05	0·74
Turkey	0·09	0·01	0·10*	0·01	0·10	0·01	0·13	0·01	0·11	0·01	0·16**	0·01	0·66
All poultry	0·53	0·05	0·64***	0·04	0·60	0·05	0·62*	0·03	0·57	0·03	0·69	0·04	0·69
Fish and shellfish	0·23	0·04	0·23	0·02	0·20	0·04	0·22	0·02	0·22	0·02	0·33	0·05	0·59
Milk and milk products	3·08	0·16	3·07	0·13	3·78	0·27	3·24	0·14	3·55	0·22	3·32	0·09	0·15
Eggs	0·33	0·02	0·32	0·03	0·32	0·02	0·33	0·01	0·33	0·02	0·30	0·02	0·95
Legumes	0·19	0·04	0·22	0·04	0·18	0·02	0·27	0·03	0·22	0·03	0·27*	0·03	0·71
Nuts and seeds	0·19	0·02	0·23	0·02	0·21	0·02	0·24***	0·03	0·21	0·02	0·26	0·01	0·95

Statistical significance of trend in types of protein within a subgroup: *P <0·05, **P <0·01, ***P <0·001.

^†A ratio of family income to poverty threshold.

^‡g/kg indicates grams of food per kilogram of body weight.