Sweet Potato Greens
September 2, 2011 Written by JP [Font too small?]I’m always on the lookout for “new” foods that I can add to my diet to keep things interesting. If these culinary additions happen to be delicious and nutrient dense, all the better. Sweet potato leaves are an excellent candidate that I’m planning to experiment with for two reasons. First and foremost, they bring robust nutrition to the table. A publication appearing in the October 2010 issue of the journal Nutrition Reviews proclaims that eating sweet potato leaves may “play a role in health promotion by improving immune function, reducing oxidative stress and free radical damage, reducing cardiovascular disease risk, and suppressing cancer cell growth”. All of these assertions and more are backed up by scientific studies in prestigious medical journals.
There’s even evidence that eating sweet potato greens may protect consumers from age-related conditions such as macular degeneration. Secondly, according to a few of my foodie friends, these dark green leafy vegetables are quite versatile and can be used in place of other, more commonly used contenders including collard greens, kale and spinach. They can also be eaten raw as complementary or primary ingredients in salads. Perhaps best of all, they’re naturally low in calories (about 20 calories per cup) and have a very low glycemic load of only 2. I hope you’ll join me in trying out this traditional food which may be as new for you as it is for me.
Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!
To learn more about the studies referenced in today’s column, please click on the following links:
Study 1 – Sweet Potato Leaves: Properties and Synergistic Interactions That … (link)
Study 2 – Sweet Potato (Ipomoea Batatas L.) Leaves Suppressed Oxidation … (link)
Study 3 – Intake of Vitamin A-Rich Foods and Lung Cancer Risk in Taiwan … (link)
Study 4 – Consumption of Purple Sweet Potato Leaves Modulates Human … (link)
Study 5 – Carotenoid Content and In Vitro Bioaccessibility of Lutein … (link)
Sweet Potato Leaves May Reduce LDL Cholesterol Oxidation
Source: J Clin Biochem Nutr. 2011 May; 48(3): 203–208. (link)
Tags: Antioxidants, Low Carb, Vegetables
Posted in Food and Drink, Heart Health, Nutrition
February 7th, 2015 at 1:10 pm
Update:
http://www.sciencedaily.com/releases/2015/01/150114101642.htm
“A study designed to determine the ascorbic acid, thiamin, riboflavin, and vitamin B6 content in foliar tissues of sweet potato confirmed that mature and young sweet potato leaves can be a good source of multiple water-soluble vitamins in the human diet. Young leaves contained the highest ascorbic acid content, followed by mature leaves and buds.”
The abstract of the study …
http://hortsci.ashspublications.org/content/49/11/1470.abstract
Ascorbic Acid, Thiamin, Riboflavin, and Vitamin B6 Contents Vary between Sweetpotato Tissue Types
Sweetpotato is considered a good source of ascorbic acid (vitamin C) and certain B vitamins. These water-soluble vitamins (WSV) play essential roles in sustaining human health. Besides the root, sweetpotato vegetative tissues are also edible and considered high in nutritional value. Despite the availability of general reference values for sweetpotato WSV content in the root and leaves, little is known about the distribution of these vitamins in specific sweetpotato root and vegetative tissues. The objective of this study was to determine the ascorbic acid (AA), thiamin (B1), riboflavin (B2), and vitamin B6 content in a range of foliar tissues including buds, vines, young petioles, young leaves, mature petioles, and mature leaves and root tissues including the skin, cortex, and pith tissue at the proximal, distal, and center regions of the root. Among foliar tissues of ‘Beauregard’ sweetpotatoes, the AA content was highest in young leaves (108 to 139 mg/100 g fresh weight) and lowest in mature petioles (7.2 to 13.9 mg). No thiamin was detected in foliar tissue, whereas mature leaves contained the highest riboflavin and vitamin B6 content (0.22 to 0.43 mg and 0.52 to 0.58 mg, respectively). In root tissues of ‘Beauregard’ and ‘LA 07-146’ sweetpotatoes, the AA content was lower in the skin (1.9 to 5.6 mg and 2.54 to 3.82 mg, respectively). The AA content in the cortex and pith tissue at the proximal, distal, and center of the root was generally similar. The thiamin content was variable among root tissues, whereas the skin contained the highest riboflavin content and the lowest vitamin B6 content across root tissues of both cultivars. The results of this study confirmed earlier reports suggesting that sweetpotato leaves can be a good source of multiple WSV in the human diet.
Be well!
JP
August 25th, 2015 at 7:23 pm
Updated 08/25/15:
http://pubs.rsc.org/en/Content/ArticleLanding/2014/FO/C4FO00032C#!divAbstract
Food Funct. 2014 Sep;5(9):2309-16.
Dietary sweet potato (Ipomoea batatas L.) leaf extract attenuates hyperglycaemia by enhancing the secretion of glucagon-like peptide-1 (GLP-1).
‘Suioh’, a sweet potato (Ipomoea batatas L.) cultivar developed in Japan, has edible leaves and stems. The sweet potato leaves contain polyphenols such as caffeoylquinic acid (CQA) derivatives. It has multiple biological functions and may help to regulate the blood glucose concentration. In this study, we first examined whether sweet potato leaf extract powder (SP) attenuated hyperglycaemia in type 2 diabetic mice. Administration of dietary SP for 5 weeks significantly lowered glycaemia in type 2 diabetic mice. Second, we conducted in vitro experiments, and found that SP and CQA derivatives significantly enhanced glucagon-like peptide-1 (GLP-1) secretion. Third, pre-administration of SP significantly stimulated GLP-1 secretion and was accompanied by enhanced insulin secretion in rats, which resulted in a reduced glycaemic response after glucose injection. These results indicate that oral SP attenuates postprandial hyperglycaemia, possibly through enhancement of GLP-1 secretion.
Be well!
JP
August 25th, 2015 at 7:25 pm
Updated 08/25/15:
http://pubs.acs.org/doi/abs/10.1021/jf502328d
J Agric Food Chem. 2014 Sep 10;62(36):8982-9.
Effects of domestic cooking methods on polyphenols and antioxidant activity of sweet potato leaves.
In this study, effects of boiling, steaming, microwaving, baking, and frying on proximate composition, total and individual polyphenol contents, and antioxidant activity of sweet potato leaves were investigated. An increase of 9.44% in total polyphenol content was observed after steaming, whereas decreases of 30.51, 25.70, and 15.73% were noted after boiling, microwaving, and frying, respectively. Decreases of 63.82 and 32.35% in antioxidant activity were observed after boiling and microwaving, respectively, whereas increases of 81.40, 30.09, and 85.82% in antioxidant activity were observed after steaming, baking, and frying, respectively. Eight phenolic compounds were identified in sweet potato leaves. The correlation analysis between content of individual phenolic compounds and antioxidant activity suggested that antioxidant activity could be mainly attributed to 4,5-di-O-caffeoylquinic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 3,4,5-tri-O-caffeoylquinic acid. It was suggested that steaming is a preferred method to maintain polyphenols and antioxidant activity of sweet potato leaves.
Be well!
JP
August 25th, 2015 at 7:26 pm
Updated 08/25/15:
http://www.sciencedirect.com/science/article/pii/S0308814614001113
Food Chem. 2014 Aug 1;156:380-9.
Sweet potato (Ipomoea batatas L.) leaves as nutritional and functional foods.
In this study, the nutritional compositions of leaves from 40 sweet potato (Ipomoea batatas L.) cultivars were assessed. The correlations between antioxidant activity and crude protein, crude fat, crude fiber, carbohydrate, and polyphenol contents were determined. The crude protein, crude fiber, crude fat, carbohydrate and ash contents ranged between 16.69-31.08, 9.15-14.26, 2.08-5.28, 42.03-61.36, and 7.39-14.66g/100gdryweight(DW), respectively. According to the index of nutritional quality, sweet potato leaves are good sources of protein, fiber, and minerals, especially K, P, Ca, Mg, Fe, Mn, and Cu. The correlation coefficient between antioxidant activity and total polyphenol content was the highest (0.76032, p<0.0001), indicating that polyphenols are important antioxidants in sweet potato leaves. Sweet potato leaves, which contain several nutrients and bioactive compounds, should be consumed as leafy vegetables in an attempt to reduce malnutrition, especially in developing countries.
Be well!
JP
August 25th, 2015 at 7:28 pm
Updated 08/25/15:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4228256/
Lipids Health Dis. 2013 Nov 5;12:168.
Diets containing traditional and novel green leafy vegetables improve liver fatty acid profiles of spontaneously hypertensive rats.
BACKGROUND: The consumption of green leafy vegetables (GLVs) has been demonstrated to reduce the risks associated with cardiovascular and other diseases. However, no literature exists that examines the influence of traditional and novel GLVs on the liver fatty acid profile of an animal model genetically predisposed to developing hypertension. The aim of the present study was to examine the effects of diets containing 4% collard greens, purslane or sweet potato greens on the liver fatty acid profiles of four-week old male spontaneously hypertensive rats (SHRs, N = 44). Following four weeks consumption of the diets, liver fatty acid profiles were determined by gas-liquid chromatography of transesterified fatty acid methyl esters.
RESULTS: SHRs consuming the control diet had greater percentages of liver saturated fatty acid and less omega-3 fatty acid percentages. SHRs consuming the diets containing vegetables had significantly greater liver concentrations of γ- linolenic, docosahexaenoic and docosahexaenoic acids, as well as lower levels of lauric, palmitic and arachidonic acids. SHRs consuming the control diet had significantly greater percentages (p < 0.05) of oleic; significantly less γ-linolenic and docosahexaenoic acids. CONCLUSIONS: This study demonstrates the ability of GLVs to modulate liver fatty acid composition, thus providing protection against elevations in atherogenic fatty acids, which may be involved in CVD pathogenesis. Consequently, dietary recommendations for the prevention of CVD should consider the possible cardioprotective benefits and the subsequent alterations in fatty acid profiles afforded by diets containing collard greens, purslane and sweet potato greens. Be well! JP