Zinc and iron are two essential minerals our bodies need for proper functioning. Zinc plays a role in healthy immune function, protein synthesis, wound healing and cell division. And iron has a number of important tasks, including carrying oxygen from the lungs to the rest of the body and helping the muscles store and use oxygen. Iron also helps the body digest food.
When we don’t have enough of either mineral, these important bodily functions suffer, which can lead to fatigue, poor immunity and illness, among other problems.
Both zinc and iron exist in the foods we eat. Some of the best sources of zinc include certain seafood (oysters, crab, lobster, flounder), beef, pork, chicken, fortified cereals, yogurt, chickpeas and milk.
Dietary sources of iron are divided into two types: heme and non-heme. Heme sources of iron basically include all animal products — organ meats, oysters, clams, poultry, beef, duck, lamb and shrimp. Non-heme sources are vegetarian in nature. Some of the top dietary sources of non-heme iron include beans, lentils, pumpkin seeds, fortified cereals, spinach, blackstrap molasses and tomato puree.
Heme iron is absorbed two to three times more efficiently than non-heme iron. This is why, oftentimes, medical professionals will tell you to eat more meat if you have low iron levels. The good news is, increasing your heme iron consumption does work to increase iron levels in the body.
The bad news, however, is that recent research has established that the intake of zinc and iron from certain animal sources may be linked to a higher risk of metabolic syndrome and cardiovascular disease.
Researchers followed 6,814 healthy, heart disease-free adults ages 45-84 for 10 years. Dietary assessments were completed using in-depth food frequency questionnaires.
After adjusting for demographics and behavioral and lifestyle factors, including body mass index, the researchers found that the consumption of heme iron and zinc from red meat, in particular, was associated with increased risk of metabolic syndrome and cardiovascular disease. On the other hand, non-heme sources of iron were not associated with increased risk of metabolic syndrome, type 2 diabetes or cardiovascular disease.
While there were no clear answers as to why they discovered this association, the researchers stated that because the intakes of heme iron and zinc from non-red meat sources had no effect on these diseases, the findings suggest that the associations might reflect that other constituents of red meat might interact with heme iron and zinc and alter their bioavailability in the body. They also said that observations from the study suggest that other elements present in red meat may influence cardiovascular disease and metabolic syndrome.
The results of this study don’t necessarily mean you have to ditch the burgers completely, although most health professionals agree that you should limit your consumption of red meat to a couple times per week at most, mainly because red meat tends to be high in saturated fat. If you do choose red meat, the American Heart Association recommends the following tips:
1. Watch your portion sizes. One 3-oz. portion of meat is about the size of a deck of cards.
2. Choose leaner cuts, which usually contain the words “round,” “loin” or “sirloin” on the package.
3. Trim off as much fat as you can before cooking, and pour off the melted fat after cooking.
4. Instead of frying, opt to bake, broil, stew or grill the meat.
If you decide to limit your meat intake and get your iron and zinc mainly from non-heme sources, there are a few precautions you should follow to help your body absorb the nutrients better. If possible, include a small portion of a heme iron source with your meals. Doing so will enhance the iron absorption from non-heme sources. Also, include vitamin C-rich foods with your meals, because this vitamin also enhances iron absorption.
 http://www.cdc.gov/nutrition/everyone/basics/vitamins/iron.html#Iron Sources
 de Oliveria Otto MC et al. Dietary intakes of zinc and heme iron from red meat, but not from other sources, are associated with greater risk of metabolic syndrome and cardiovascular disease. J Nutr. 2012 Mar;142(3):526-33.