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| Image 1: Looks like color matters! The yellow variety of Passiflora edulis is not just a particularly rich source of low-methoxyl pectin (dietary fiber), it's also packed with other bioactive substances which could keep you lean and healthy! |
The title of the paper Sandra Maria Barbalho and colleagues published in the
Journal of Diabetes Research & Clinical Metabolism a couple of days ago is quite telling "
Yellow passion fruit rind (Passiflora edulis): an industrial waste or an adjuvant in the maintenance of glycemia and prevention of dyslipidemia?", as it does imply that we could once again have missed an important part of the whole picture in our never-ending strive for ever maximal standardization, isolation and convenience: The waste that is generated from Brazil's 35,000 hectare passion fruit industry, more than 317,000 metric tons of fiber-, mineral., vitamin-, phenol- and flavenoid-laden
flavedo (colored part of the rind) and
albedo (white part of the rind) from
Passiflora edulis.Passion Fruit Rind - Nothing in Nature is Wasted!If we dig somewhat deeper into the archives of the medical, chemical and even historico-cultural journals, it's not as if we could not have known about the potential health benefits of the putative "natural packaging" that protects the juicy kernel of the fruits of a plant which belongs to the family
Passifloracea and originated in the tropical and subtropical regions of the American continent. Previous studies by Deng, Janebro and Ramos, for example, did already hint at the potent
anxiolytic,
antihyperglycemic and antihyperlipedemic effects of a fruit that has a longstanding tradition in traditional medicine (Ramos. 2007; Janebro. 2008; Deng. 2010). Against that background, it is almost surprising that the existent literature on the use of respective extracts is not exactly comprehensive.
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| Figure 1: Changes in body weight (in g), absolute serum values (mg/mL) for glucose, triglycerides, cholesterol (total), HDL-C and LDL-C after 30 days of either regular or passion fruit bark powder solution (2x 1ml/kg body weight) supplemented diet in healthy Wistar rats (data adapted from Barbalho. 2013) |
Malicious gossip would probably have it that the surprisingly profound effects Barbalho et al. observed in
healthy rodents in response to the twice-daily administration of 1ml/kg bodyweight of a quasi-homemade (see infobox on the right of the next paragraph for details), obviously non-patentable passion fruit extracts would hamper the sales of
metformin,
lipitor and the recently FDA-approved weight loss drug
Belviq (a 5-HTC-2 serotonin receptor antagonist). After all, aside from the decrease in LDL,
all the diabetes- and CVD relevant changes in figure 1 were statistically highly significant (p<0.01); and what's more, the necessary raw material is not just looked down upon, as if it was a waste product, it is according to the authors also treated like any other industrial waste by Brazil's passion fruit juice industry who either dumps it on illegal landfills or has to pay money for its proper disposal (Barbalho. 2013).
My GNC Does Not Have Passion Fruit Rind Extracts! Can I Make My Own? How to home-brew your own PFR extract ;-)- dehydrate the rind on trays in a forced air circulation drying oven at 55ºC until a constant dry weight is reached
- ground 200g into powder in a multiprocessor for 6 minute (turn off the processor at 2 min intervals to stir the product)
- prepare a solution of 20 g of powdered rind and 500 mL of water
- beat solution in a blender for 12min
- filtered through filter paper
- divide resulting solution into aliquots and stored in a freezer at -10ºC
Ingest 2x10-14ml servings per day (standard
HED calculation)
Ecology and health aside, I bet that for (too) many people
the -76% reduction in weight gain would constitute the most convincing argument to buy Passion-o-Lean(TM) or whatever stupid name the first company whose "product designer" reads the study will come up with ;-)
Now, the good news is that we do actually have human data to confirm a statistically significant weight loss effect from passion fruit rind products: The nineteen 30-60 year-old, still normal-weight (BMI 24.8kg/m²) but hyperlipidemic (cholesterol > 200 mg/dL; went down by -18% as a result of supplementation)
women in the aforementioned study by Ramos et al. lost 1.7 kg within one month (Ramos. 2007), but
they did ingest 30g of passion flower rind flour per day and
the weight loss stalled in the second month in the course of which they lost <300g, only - by no means as impressive as the weight loss, or, I should say, the absence of weight gain in the rodents from Barbalho study, right?
Due to the fact that Ramos et al. don't disclose how the co-authoer Sabaasrur, who provided the flour, actually prepared it, we cannot definitely answer the question whether or not these differences could simply be a result of the different preparation methods and consequent yield of bioactive substances in the extract (Barbalho. 2013) and the flour (Ramos. 2007). It is however very unlikely that the production of the floor involved either
low temperature drying (1), water extraction (3-5) or refrigeration to maintain the maximal vitamin and phenols content (see
figure 2) as they were part of the manual extraction process that was used in the Barbalho study (for details on the preparation see box on the left).
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| Figure 2: If you are more of a juicer, make sure to drink your juice right away to get the maximum amount of the good phenolic acids and avoid the potentially hazardous HMF (click to enlarge for more info; data based on Talcott. 2003) |
Implications: Despite the fact that the data in
figure 2, though based on an analysis of passion fruit juice, would support the hypothesis that the handmade passion fruit rind extract in the Barbalho study was more than just one magnitude "stronger" than the flour that's been used with some success in the Ramos and the Janebro study, it is still questionable, whether the profound
reductions in blood glucose, the
improvements in the triglyceride (1.3 vs. 4.3) and
total cholesterol to HDL ratios (2.5 vs. 10.4) will translate 1:1, or even at all to human beings. After all, it could be partly mediated by the reduced weight gain... apropos, 'not gaining weight' is still very different from 'losing weight' and it is therefore not feasible to compare, the relatively mediocre weight loss in the Ramos study, of which the scientists assume that it was, just as the reduction in cholesterol,
mediated by the high content of soluble fiber in the passion fruit flour (73% of the dry matter is fiber, 60% of it insoluble; Yapo. 2008), to the profound 'anti-obesity' effect in the Barbalho study.
Moreover, in the absence of detailed information about the body composition of the lab animals and their energy intake, we could as well be dealing with the results of
micronutrient malabsorption or
anorexia as root causes of the reduced body weight in the passion fruit rind extract group of the Barbalho study.... although, with the twice daily bolus administration of only 2x 1ml of the PFR extract, both explanations, i.e. 'failure to thrive due to nutrient malabsorption' and 'anorexia in response to too much fiber', appear pretty unlikely, so that
passion fruit rind extract would actually be a good candidate for a home-brew diabesity prevention potion... well, at least if you live next to one of those Brazilian dumping grounds where the passion fruit industry disposes of their hitherto unrecognized treasures ;-)
- Barbalho SA, da Silva Soares de Souza M, de Paula e Silva J, Mendes CG, de Oliveira GA, Costa T, Farinazzi-Machado. Yellow passion fruit rind (Passiflora edulis): an industrial waste or an
adjuvant in the maintenance of glycemia and prevention of dyslipidemia? FMV. Journal of Diabetes Research and Clinical Metabolism. 2013. - Deng J, Zhou Y, Bai M, Li H, Li L: Anxiolytic and sedative activities of Passiflora edulis f. flavicarpa. J Ethnopharmacol 2010; 128;(1.);148-53.
- Janebro D I, Queiroz M S R, Ramos A T, Sabaa-Srur A U O, Cunha MAL, Diniz M F. Effect of the flour of the yellow passion fruit peel (Passiflora edulis f. flavicarpa Deg.) in the glycemic and lipid levels of type 2 diabe- tes patients. Rev Bras Farmacog 2008;18: 723-732.
- Ramos AT, Cunha MAL, Sabaasrur AUO, Pires VCF, Cardoso AA et al. Use of Passiflora edulis f. flavicarpa on cholesterol reduction. Braz J Pharmacog 2007;17: 592-560.
- Talcott ST, Percival SS, Pittet-Moore J, Celoria C. Phytochemical composition and antioxidant stability of fortified yellow passion fruit (Passiflora edulis). J Agric Food Chem. 2003 Feb 12;51(4):935-41.
- Yapo BM, Koffi KL: Dietary fiber components in yellow passion fruit rind - a potential fiber source. J Agric Food Chem 2008; 56;(14.);5880-3.
