The nutritional value of margarine is still the focus of controversial debates. Although margarine has been advertised by companies for years as having many health benefits, scientific findings have found that several of these claims are simply not true. As a result, manufacturers have made adjustments; for example, they have reduced the amount of trans fats and now use carotenoids as a dye instead of “butter yellow,” which was found to be carcinogenic. Cold-pressed coconut oil or almond butter are unrefined natural organic products that in many cases are a better alternative.
From Wikipedia: “Margarine is an imitation butter spread used for spreading, baking, and cooking. Hippolyte Mège-Mouriès created it in France, in 1869. He was responding to a challenge by Emperor Napoleon III to create a butter substitute for the armed forces and lower classes. It was later named margarine.
Margarine, like butter, consists of a water-in-fat emulsion, with tiny droplets of water dispersed uniformly throughout a fat phase in a stable crystalline form. In some jurisdictions margarine must have a minimum fat content of 80% to be labelled as such, the same as butter.”
Manufacturing process and ingredients:
“If hydrogenation is incomplete (partial hardening), the relatively high temperatures used in the hydrogenation process tend to flip some of the carbon-carbon double bonds into the "trans" form. If these particular bonds aren't hydrogenated during the process, they remain present in the final margarine in molecules of trans fats, the consumption of which has been shown to be a risk factor for cardiovascular disease. For this reason, partially hardened fats are used less and less in the margarine industry. Some tropical oils, such as palm oil and coconut oil, are naturally semi-solid and do not require hydrogenation. ...
The oil is pressed from seeds and refined. It is then blended with solid fat. If no solid fats are added to the vegetable oils, the latter undergo a full or partial hydrogenation process to solidify them. The resulting blend is mixed with water, citric acid, carotenoids, vitamins and milk powder. Emulsifiers such as lecithin help disperse the water phase evenly throughout the oil, and salt and preservatives are also commonly added. This oil-and-water emulsion is then heated, blended, and cooled. The softer tub margarines are made with less hydrogenated, more liquid, oils than block margarines.”
“Organic margarines contain semi-solid palm oil or coconut oil and are manufactured using special emulsion processes. They usually donʼt undergo the process of chemical hydrogenation.*”
“Scientific research once indicated that margarine was healthier than butter. As with other vegetable fats, margarine contains very little cholesterol, which is seen as positive for our health. More recent studies no longer confirm this view.*”
Hydrogenated fats: “Margarine, which consists primarily of hydrogenated fats contains hardly any essential fatty acids and the process of partial hydrogenation results in trans fats. As a result, soft margarines containing non-hydrogenated oil, essential unsaturated fatty acids, and only small amounts of cholesterol and trans fats are increasingly recommended.*”
Added vitamins: “Since most vitamins are destroyed during hydrogenation, vitamins are often added to margarine after this process. ... However, vitamin-enriched foods are now viewed critically by the scientific community.*”
Glycerol fatty acid esters: “The glycerol fatty acid esters that arise during the refining process are considered problematic. When palm oil is used, the concentration of this harmful substance is particularly high. In 16 of 19 margarines, Öko-Test (German consumer magazine) found this precursor of the genotoxic and likely carcinogenic glycidol. It is therefore best to choose a semi-solid margarine, which has fewer glycerol fatty acid esters as a result of the higher water content.*”
Note (italics): * = Translation from a German Wikipedia entry