'Rise of saturated fat in diet does not raise fats in blood'

A new controlled diet study has found that increasing the levels of saturated fat in the diet does not lead to increased levels of saturated fat in the blood. However, increasing the amount of carbohydrates in the diet was found to raise the levels of a fatty acid associated with diabetes and heart disease.

Diets full of high carbohydrate foods such as cookies could increase the risk of heart disease, according to research. Levels of palmitoleic acid were reduced with low carbohydrate intake and increased as the participants consumed progressively larger amounts of carbohydrates over the course of the study.
According to senior author Prof. Jeff Volek, the study, "challenges the conventional wisdom that has demonized saturated fat and extends our knowledge of why dietary saturated fat doesn't correlate with disease."
In the study, published in PLOS ONE, the authors state that current dietary guidelines in the US recommend the majority of calories should be acquired from carbohydrates, with only 7-10% of total energy coming from saturated fats.
To achieve this, foods containing saturated fat - beef, eggs, high-fat dairy products - should be limited. Typically, a reduction in these foods results in an increased consumption of carbohydrates.
"People believe 'you are what you eat,'" says Prof. Volek, "but in reality, you are what you save from what you eat. The point is you don't necessarily save the saturated fat you eat. And the primary regulator of what you save in terms of fat is the carbohydrate in your diet."

Dietary saturated fat not linked to palmitoleic acid

The study involved 16 adults being given six 3-week diets - each containing 2,500 calories and around 130 grams of protein - that progressively increased the participants' levels of carbohydrates while reducing their consumption of total fat and saturated fat.
Each of the participants had metabolic syndrome - a number of simultaneously occurring conditions that increase the risk of diabetes, stroke and heart disease. People with metabolic syndrome have at least three of the following conditions: abnormal blood cholesterol, high blood sugar, high blood triglycerides, hypertension and obesity.
The researchers spent 3 weeks to get the participants to a baseline reduced carb diet before beginning the 18-week study. The first diet of the study consisted of 47 g of carbohydrates and 84 g of saturated fat daily, with the carb-saturated fat ratio progressively increasing until the final diet, consisting of 346 g of carbs and 32 g of saturated fat daily.
In this final diet, the carb level represented 55% of the participants' daily calories, a figure that is approximately the same as the estimated daily percentage of energy provided by carbohydrates in the American diet.
Across the study, levels of saturated fat in the blood of the participants decreased. Blood glucose, insulin levels and blood pressure also improved and, on average, the participants lost nearly 22 lb by the end of the 18 weeks.
Levels of palmitoleic acid - a fatty acid associated with obesity, insulin resistance, and heart disease - decreased in all of the participants during the high-fat/low-carb diets. In contrast, the acid was found to increase as the levels of carbohydrates progressively rose across the duration of the study.
Increases in palmitoleic acid indicate that more carbs are being converted to fat instead of being burned as fuel, states Prof. Volek. In contrast, reducing carbs and increasing dietary fat in a well-controlled way ensures that the body will burn the saturated fat as fuel, rather than storing it in the body.

Misunderstanding about dietary saturated fat is 'not smart'

The study authors hoped to discover at which point in the increased intake of carbs that the participants began to store fat in their bodies rather than burning it off. Although palmitoleic acid levels increased in all participants, the moment when fat began to be stored varied widely. This finding supports the idea that individual tolerances to carbs can be dramatically different.
Prof. Volek says that there is widespread misunderstanding about saturated fat, stating that despite population studies failing to find a link between dietary saturated fat and heart disease, dietary guidelines continue to advocate restriction of saturated fat:

"That's not scientific and not smart. But studies measuring saturated fat in the blood and risk for heart disease show there is an association. Having a lot of saturated fat in your body is not a good thing. The question is, what causes people to store more saturated fat in their blood, or membranes or tissues?"

The authors acknowledge that the study is limited by the relatively short timeframe that the diets were followed for. However, a small number of the participants were given the diets in reverse order, starting with the highest carb diet, and the same observations regarding palmitoleic acid were made.
"A higher proportion of plasma saturated fat is related to increased risk of diabetes and heart disease," conclude the authors. "Thus, there is a need to better understand the relationship between dietary and plasma saturated fat."
Recently, Medical News Today reported on an analysis of clinical trials for four popular diets, questioning the long-term benefits of the Atkins, South Beach, Weight Watchers and Zone diets.
Written by James McIntosh

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Cure for baldness? Hair-follicle-generating stem cells bring hope

According to the American Hair Loss Association, two-thirds of men will experience hair loss by the age of 35. But women are also affected, making up 40% of all hair loss sufferers. Affecting self-image and emotional well-being, the condition has been a difficult one to treat. But a new study brings hope - in the form of human hair-follicle-generating stem cells.
Researchers from the Perelman School of Medicine at the University of Pennsylvania have published results of their study in Nature, where they describe the method by which they were able to convert adult cells into epithelial stem cells (EpSCs).
Although using stem cells to regrow hair follicles has been a potential technique for combatting baldness, until now, nobody has been able to produce enough of these cells.
The team says they are the first to achieve this result in either humans or mice.
Led by Dr. Xiaowei "George" Xu, associate professor of pathology and laboratory medicine and dermatology at the University of Pennsylvania, the scientists started their research by using human skin cells called dermal fibroblasts.

How did the team produce the cells?

The researchers converted the human skin cells into induced pluripotent stem cells (iPSCs) by adding three genes. These iPSCs are able to change into any cell types in the body, so the researchers converted them into epithelial stem cells, which are normally found in a part of hair follicles.

The arrows show hair shafts, which were formed by iPSC-derived epithelial stem cells.
Image credit: Ruifeng Yang, Perelman School of Medicine, University of Pennsylvania

Using techniques from other research teams to convert iPSCs into keratinocytes - a main cell type in the top layer of the skin - Dr. Xu and colleagues showed they could "force" the iPSCs to make large quantities of EpSCs by controlling the timing of growth factors the cells received.
When they implanted these EpSCs into mice, the cells regenerated cell types of human skin and hair follicles, and also created recognizable hair shafts, which the team says shows promise for eventually regrowing hair in humans.
In 18 days, 25% of the iPSCs converted into EpSCs, which were then purified using the proteins expressed on their surfaces, the team notes.

Technique 'not yet ready for humans'

After mixing the human-derived EpSCs with dermal cells from mice, the team grafted them onto the skin of the mice and produced a functional human epidermis - the outermost layers of the skin.
The hair follicles that were produced from this, notes the team, were structurally similar to human hair follicles.
Dr. Xu says that this "is the first time anyone has made scalable amounts of epithelial stem cells that are capable of generating the epithelial component of hair follicles," adding that the cells could aid in wound healing, cosmetics and hair regeneration.
However, these cells are not yet ready for use in humans because the team has only solved one part of the equation. A hair follicle contains both epithelial cells and a certain kind of adult stem cell called dermal papillae.
Dr. Xu explains:

"When a person loses hair, they lose both types of cells. We have solved one major problem, the epithelial component of the hair follicle. We need to figure out a way to also make new dermal papillae cells, and no one has figured that part out yet."

However, he adds that stem-cell researchers are beginning to use new strategies using only chemical agents, which could result in more solutions.
In late 2013, Medical News Today reported on a study that showed how scientists successfully grew human hairs from dermal papilla cells taken from the inside of donor hair follicles, suggesting we are a step closer to a cure for baldness.

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