What are synthetic fats?
In the context of nutrition, the term 'synthetic fat' most commonly refers to artificial or industrial trans fats. These are created in a laboratory setting, not grown or produced naturally. They are distinct from the very small amounts of naturally occurring trans fats found in the meat and dairy products of ruminant animals like cattle and sheep. The synthetic version is chemically manufactured for specific commercial purposes, namely to enhance the shelf life and texture of processed foods. The process responsible for creating this type of fat is known as partial hydrogenation.
Historically, other types of synthetic fats, such as the fat substitute Olestra, were developed for use in low-calorie snack foods. While technically synthetic and non-caloric, Olestra was never widely adopted due to side effects like gastrointestinal distress and poor vitamin absorption. However, the most prevalent and harmful type of synthetic fat is the artificial trans fat, which has been the focus of major public health campaigns and regulatory action.
The process of partial hydrogenation
Artificial trans fats are the product of an industrial chemical process called partial hydrogenation. This process involves adding hydrogen to liquid vegetable oils, like soybean or canola oil, in the presence of a metal catalyst. This causes the oil to become semi-solid or solid at room temperature, a desirable quality for products like margarine and shortening. The process also prevents the oil from going rancid as quickly, extending the shelf life of baked and fried goods.
During hydrogenation, the molecular structure of the unsaturated fatty acids is changed. Some of the carbon-carbon double bonds are saturated with hydrogen, while others are shifted from a cis to a trans configuration. This molecular change is what gives the fat its stability and makes it particularly damaging to cardiovascular health. While the process has been used for over a century, the severe health consequences only became widely known in the 1990s, leading to a global re-evaluation of its use.
Health consequences of artificial trans fats
Unlike other dietary fats, artificial trans fats offer no health benefits and are dangerous even in small quantities. Their detrimental effects are well-documented and primarily impact cardiovascular health. Consumption of artificial trans fats:
- Increases LDL ('bad') cholesterol levels in the bloodstream.
- Lowers HDL ('good') cholesterol levels.
- Promotes systemic inflammation, a risk factor for heart disease, stroke, and diabetes.
- Contributes to insulin resistance, raising the risk of type 2 diabetes.
This double-negative effect on cholesterol—increasing the bad kind while decreasing the good kind—makes artificial trans fat particularly hazardous. It is widely considered the worst type of fat for heart health.
Regulatory action and consumer awareness
Following extensive research and public health campaigns, many countries have moved to limit or ban artificial trans fats. In the United States, the Food and Drug Administration (FDA) determined in 2015 that partially hydrogenated oils (PHOs) were no longer “Generally Recognized as Safe” (GRAS). This led to a phased ban on their use in most processed foods, with full implementation by 2021. The World Health Organization (WHO) also launched a global initiative to eliminate industrial trans fats.
For consumers, it is still crucial to read ingredient labels, as trace amounts (less than 0.5 grams per serving) may still be present in some foods, and regulations vary by country. Looking for the terms “partially hydrogenated oil” or “hydrogenated vegetable oil” in the ingredient list is the best way to spot this synthetic fat. However, with increased awareness, many companies have voluntarily reformulated their products to remove them entirely.
Comparison: Artificial vs. Natural Trans Fats
While both are referred to as 'trans fats,' their origins and effects differ significantly.
| Feature | Artificial Trans Fats | Natural Trans Fats |
|---|---|---|
| Source | Industrially produced by partial hydrogenation of vegetable oils. | Formed naturally by bacteria in the digestive system of ruminant animals. |
| Chemical Composition | A mix of various trans-fatty acid isomers, some of which are not found naturally. | Includes conjugated linoleic acid (CLA) and vaccenic acid. |
| Health Impact | Associated with increased LDL cholesterol, reduced HDL cholesterol, inflammation, heart disease, and diabetes. | In moderate amounts, evidence suggests they may not have the same negative health impact as artificial trans fats. |
| Primary Dietary Sources | Found in processed foods like certain margarines, shortenings, baked goods, and fried foods. | Found in small quantities in beef, lamb, and dairy products like butter and milk. |
| Regulatory Status | Largely banned or heavily restricted in many countries due to significant health risks. | Not subject to the same regulatory bans as artificial trans fats. |
Moving towards healthier alternatives
As consumers and manufacturers move away from artificial trans fats, the focus is on healthier alternatives. The ideal replacement for synthetic fats comes from sources rich in unsaturated fats, which include both monounsaturated and polyunsaturated fats.
Examples of healthier fat sources:
- Monounsaturated Fats: These are found in liquid oils like olive oil, canola oil, and peanut oil. They are also present in avocados and most nuts.
- Polyunsaturated Fats: Found in fatty fish (salmon, mackerel), flaxseeds, walnuts, and vegetable oils such as corn, sunflower, and soybean oil.
- Natural Oils and Fats: High-quality cooking oils and fats that are not hydrogenated, such as non-hydrogenated margarine spreads, offer better nutritional profiles.
Replacing artificial trans fats with these healthier options not only helps avoid the risks associated with synthetic fats but can also provide beneficial nutrients, like essential fatty acids and fat-soluble vitamins.
Conclusion
The answer to what type of fat is synthetic? points directly to the dangerous artificial trans fats created through partial hydrogenation. While historical attempts to create low-calorie fat substitutes like Olestra also exist, artificial trans fats in processed foods represent the most significant public health concern. Fortunately, informed consumers and global regulations have led to a substantial reduction in their presence in the food supply. By understanding the chemical nature and health risks of synthetic fats and choosing healthier alternatives, individuals can make better dietary decisions for their cardiovascular health. The key takeaway is simple: read ingredient labels, prioritize unprocessed foods, and opt for natural sources of fat rich in unsaturated fatty acids.
For more information on dietary fats and healthy eating, visit the American Heart Association website. American Heart Association
