Monday, January 6, 2014

Almonds and Sunflower Kernels Equally Beneficial for Type II Diabetics: If Anything, There is s Small Advantage For Sunflower + Grape See Oil vs. Almonds + Olive Oil

Almonds + olive oil vs. sunflower kernels + grape seed oil - what's better for your health?
Despite the fact that they are seeds, not nuts, and contain a truckload of omega-6 fatty acids, even some of the n-6-phobic health fanatics will probably agree that almonds make an excellent snack that's equally suitable for weight loss, weight maintenance and weight gain diets.

Sunflower kernels, on the other hand, have a very bad rep; and I honestly haven't seen any of the online health gurus recommend them as a healthy snack alternative - let alone as a possible replacement for almonds. Against that background I was intrigued, when I hit upon a study that compared the effects of 30g the two "health snacks" in a group of 22 postmenopausal women (mean age 62 ± 5.7 years) with type 2 diabetes (Richmond. 2013).

Almonds or sunflower kernels... believe it or not, it doesn't even matter!

According to the results of Korina Richmond's, Sheila Williams', Jim Mann's, Rachel Brown's, and Alexandra Chisholm's study, which was published a whole year after it had been accepted for publication in the peer-reviewed scientific journal ISRN Nutrition almonds and sunflower kernels are equally effective adjuncts to a diabetes guideline conform diet, of which Richmond et al. write:
"The diets were designed to provide 30% total energy from fat of which 8% was to come from saturated fat, 15% or 9% from monounsaturated fat, and 6% or 12% from polyunsaturated fat in the AD and SKD diets, respectively. Carbohydrate and protein were to provide 51% and 17% total energy, respectively. The dietary fibre target was 25–35 g and dietary cholesterol ≤ 200mg per day." (Richmond. 2013)
The 30g/day of almonds and sunflower kernels, the researchers had selected because "they have a similar amount of saturated fat per 100 g and similar total amounts of unsaturated fats", but differ in their monounsaturated (high in almonds) and polyunsaturated fat (high in sunflower kernels) content, were simply added on top of the baseline diet from Monday to Friday and had to be consumed as part of the midday meal.

Designed to isolate the effects of the different fatty acid compositions

Moreover, the "small amounts of added fats and oils needed for spreading, baking, or cooking reflected the composition of the almonds and sunflower kernels." Practically speaking this means that the subjects had to use a predominantly monounsaturated spread (Olivio, Unilever, Auckland, New Zealand) and olive oil (Lupi Extra Virgin, William Aitken & Co., Auckland, New Zealand) as their main fat source, if they had been assigned to the almond.
Figure 1: Diet composition (in g), left; corresponding MUFA:PUFA ratio, right (Richmond. 2013)
The subjects in the sunflower group, on the other hand, had to stick to a highly polyunsaturated spread (Meadow Lea, Goodman Fielder, Auckland, New Zealand) and grape seed oil (Azalea, William Aitken & Co., Auckland, New Zealand). As the scientists point out, this ensured that
"the nutrient composition of the AD and SKD was planned to be essentially the same apart from the differing fatty acid composition". (Richmond. 2013)
For us, the standardization of the diets the subjects followed for 2x3 weeks with a 4-week wash-out period in-between is what makes this study so interesting. Despite the fact that I'd guess that only a minority of SuppVersity readers is female and over the age of 65, the minimal differences between the high MUFA + medium PUFA and the medium PUFA + high MUFA diets is still highly informative; it does after all fly in the face of the hypothesis that even nuanced increases in N-6 intake would have inavoidable, highly detrimental negative side effects on our metabolic health.
Figure 2: Relative change in lipid and lipoprotein concentrations, blood pressure, and alpha-tocopherol; only the inter-group differences for trigs, Apo A1 and B100 were stat. sign (Richmond. 2013)
As the data in Figure 2 goes to show you, those negative side effects simply don't exist. On the contrary, if we went by the effects of the almond and sunflower kernel diets on lipid and lipoprotein concentrations, blood pressure, and -tocopherol, sunflower kernels + grape seed oil actually appear to be the healthier alternative.
Figure 3: Relative change in blood glucose, HbA1C and insulin levels after 3 weeks on the respective diets (Richmond. 2013)
Bottom line: In view of the fact that the allegedly inferior sunflower kernel + grape seed oil diet had significantly more beneficial effects on triglycerides, Apo A1 and Apo B100, the study at hand puts a huge question-mark behind the widely held belief that sunflower kernels had to be avoided like the plague.
Moreover, despite a 3.4x higher MUFA:PUFA ratio the sunflower kernel + grap seed oil diet did also lead to non-significantly more pronounced improvements in blood glucose management, as well (see Figure 3). So, just in case there is are a dozen of sunflower kernels on the salad you order in a restaurant, don't freak out. They are not going to kill you - I promise ;-)
References:
  • Richmond, K., Williams, S., Mann, J., Brown, R., & Chisholm, A. (2013). Markers of Cardiovascular Risk in Postmenopausal Women with Type 2 Diabetes Are Improved by the Daily Consumption of Almonds or Sunflower Kernels: A Feeding Study. ISRN Nutrition, 2013.