While salad may be a great way to mainline your five-a-day, you won't get much benefit without the right type and amount of salad dressing, a Purdue University study suggests.
Researchers measured the levels of carotenoids absorbed by individuals after they ate salads topped off with saturated, monounsaturated and polyunsaturated fat-based dressings.
Carotenoids, such as lutein, lycopene, beta-carotene and zeaxanthin compounds, have been associated with reduced risk of several chronic and degenerative diseases such as cancer, cardiovascular disease and macular degeneration.
The study, published in the journal Molecular Nutrition & Food Research, found that monounsaturated fat-rich dressings required the least amount of fat to get the most carotenoid absorption, while saturated fat and polyunsaturated fat dressings required higher amounts of fat to get the same benefit.
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"If you want to utilize more from your fruits and vegetables, you have to pair them correctly with fat-based dressings," said Mario Ferruzzi, the study's lead author and a Purdue associate professor of food science, in statement.
"If you have a salad with a fat-free dressing, there is a reduction in calories, but you lose some of the benefits of the vegetables."
Fat substitutes in food have also been associated with health problems, such as metabolic syndrome and weight gain.
Another study by Purdue University last year found that synthetic fat substitutes used in low-calorie potato chips and other foods could backfire and contribute to weight gain and obesity
Rats on high-fat diet gained more weight after eating low-calorie potato chips made with fat substitutes, which challenges the conventional wisdom that foods made with fat substitutes help with weight loss.
For rats on the high-fat diet, the group that ate both types of potato chips consumed more food, gained more weight and developed more fatty tissue than the rats that ate only the high-calorie chips.
The fat rats also didn't lose the extra weight even after the potato chips were removed from their diet.
"Based on this data, a diet that is low in fat and calories might be a better strategy for weight loss than using fat substitutes," Swithers said.
Another study has also found an association between high diet cola consumption and large waist circumference, and additional research has also found a link to heart attack and stroke risk.