The beneficial effects and clinical studies of kale

1. FOOD AS MEDICINE:
KALE
BRASSICA OLERACEA (ACEPHALA)
By
Kevin KF Ng, MD, PhD.
Former Associate Professor of Medicine
University of Miami, Miami, FL., USA.
Email: kevinng68@gmail.com
A slide presentation for HealthCare Providers Nov 2021

2. PresentationOutline
▪ What is kale?
▪ Varieties of kale.
▪ Classification of kale
▪ Scientific studies
▪ Nutrient composition
▪ Phytochemical studies
▪ Safety issues
▪ Summary

3. WHAT IS KALE ?

4. What is kale?
▪ Kale is a vegetable and a member of the
cabbage (brassica oleracea) family.
▪ It is a cruciferous vegetable like cabbage,
broccoli, cauliflower, collard greens and
Brussels sprouts.
▪ The origin of kale is unknown
▪ There are many different types of kale.

5. Varieties of kale

6. Varieties of a single magical plant species
https://www.vox.com/xpress/2014/8/6/5974989/kale-cauliflower-cabbage-broccoli-same-plant

7. Top kale producing countries in th e world
https://www.tridge.com/intelligences/kale/export

8. Food Trends Each State loved From The Past Decade
(Based on Google Trends Data) Jan 2020
https://www.ktnv.com/positivelylv/top-food-trends-of-the-decade-by-state

9. Kale Is Good and Lots of People Still Like It (2019)
https://slate.com/business/2019/10/kale-good-popular-atlantic-wrong.html

10. SCIENTIFIC CLASSIFICATION
SCIENTIFIC STUDIES

11. Scientific classification of kale
https://en.wikipedia.org/wiki/Kale

12. Number of articles on “kale” in PubMed from
1904 to 2020
https://pubmed.ncbi.nlm.nih.gov/?term=kale

13. NUTRIENT COMPOSITION
PHYTOCHEMICALS

14. Macronutrient & micronutrient compositions per 100 g raw kale
https://fdc.nal.usda.gov/fdc-app.html#/food-details/1103116/nutrients

15. Major Phytochemicals in Kale

16. Some properties of phytochemicals in kale:
solubility, bioavailability & half life

17. ● PHARMACOLOGICAL ACTIVITIES
● BIOAVAILABILITY OF
GLUCOSINOLATES, FLAVONOIDS, PHENOLICS

18. Pharmacological activities of Kale
▪ Antioxidant
▪ Anti-inflammatory
▪ Immuno-modulatory
▪ Anticancer
▪ Hypoglycemic
▪ Hypolipidemic
▪ Hypotensive

19. Absorption of glucosinolates and their breakdown products
in the human gut. (2016)
https://www.frontiersin.org/articles/10.3389/fnut.2016.00024/full

20. Metabolism of flavonoids by gut microbiota
(2021)
https://www.researchgate.net/figure/Illustration-of-flavonoids-metabolism-by-gut-microbiota-After-the-ingestion-of_fig1_353686805

21. Interactions between dietary flavonoids and the gut microbiome:
a comprehensive review (2021)
https://www.cambridge.org/core/journals/british-journal-of-
nutrition/article/abs/interactions-between-dietary-flavonoids-and-the-gut-
microbiome-a-comprehensive-review/1E2CB10A973E0BBF2FB6AE384A4B84E1

22. EFFECTS OF COOKING

23. Cooking techniques improve the levels of bioactive compounds
and antioxidant activity in kale and red cabbage (2016)
▪ The aim of this study is to investigate the effects of different home cooking techniques
(boiling, steaming, and stir-frying) in kale and red cabbage, on the levels of bioactive
compounds (carotenoids, anthocyanins and phenolic compounds) determined by high-
performance liquid chromatography coupled with photodiode array and mass
spectrometry detectors (HPLC-DAD-MS(n)), and on the antioxidant activity evaluated by
ABTS, ORAC and cellular antioxidant activity (CAA) assays.
▪ The steaming technique resulted in a significant increase in phenolic content in kale
(86.1%; p<0.001) whereas in red cabbage it was significantly reduced (34.6%; p<0.001).
In the kale, steaming resulted in significant increases in antioxidant activity levels in all
of the evaluation methods. In the red cabbage, boiling resulted in a significant increase
in antioxidant activity using the ABTS assay but resulted in a significant decrease using
the ORAC assay.
▪ According to the CAA assay, the stir-fried sample displayed the highest levels of
antioxidant activity.
▪ Keywords: Anthocyanins; Antioxidant activity; Carotenoids; Cooked vegetable; Cooking
technique; Phenolic compounds.
https://pubmed.ncbi.nlm.nih.gov/26593594/

24. The amount of flavonols in fresh and cooked kale samples (2016)
https://www.tandfonline.com/doi/full/10.1080/10942912.2016.1188308

25. Effects of cooking methods on phenolics of kale (2016)
Adapted from https://www.tandfonline.com/doi/full/10.1080/10942912.2016.1188308

26. PRE-CLINICAL & CLINICAL STUDIES

27. Reported beneficial effects of Kale
▪ Antioxidant
▪ Anti-inflammatory
▪ Immuno-modulatory
▪ Anticancer
▪ Hypoglycemic
▪ Hypolipidemic
▪ Hypotensive
▪ Metabolic syndrome
▪ Cardiovascular disease

28. Immunostimulatory in Vitro and in Vivo Effects of a Water-
Soluble Extract from Kale (2011)
▪ The water-soluble fraction of kale (Brassica oleracea L. var. acephala DC.) had
immunoglobulin (Ig) production stimulating activity in human hybridoma HB4C5 cells
and human peripheral blood lymphocytes.
▪ The biochemical and physical properties of the main active substance in kale were
found to be a heat-stable protein with a molecular weight higher than 50 kDa. The Ig
production-stimulating factors were assumed to act on the translational and/or
secreting processes of Igs. T
▪ This Ig production-stimulating effect was also observed in lymphocytes from the
mesenteric lymph node and Peyer's patches of mice that had been administered
with the kale extract for 14 d.
▪ The partially purified kale extract was analyzed by LC-ESI-MS/MS, the result
indicating ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) as an active
substance. Rubisco from spinach indeed exhibited Ig production-stimulating activity
in HB4C5 cells. These findings provide another beneficial aspect of kale as a
health-promoting foodstuff.
https://www.researchgate.net/publication/49749172_Immunostimulatory_in_Vitro_a
nd_in_Vivo_Effects_of_a_Water-Soluble_Extract_from_Kale

29. Kale suppresses postprandial increases in plasma glucose:
A randomized, double-blind, placebo-controlled, crossover study (2016)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5103670/

30. Change of plasma lipid levels of the subjects by GSTM1 and GSTT1
genotype after kale juice supplementation.(2015)
Nutrition Research and Practice 2015;9(1):49-56
Cholesterol TG HDL-C LDL-C

31. Effects of Kale Powder on BP in Subjects with Potential Metabolic Syndrome:
A Prospective Single-Arm Clinical Study (2016)
https://openaccesspub.org/jhc/article/391
SBP
DBP

32. Effect of green leafy and cruciferous vegetable (cauliflower, cabbage, cress,
bok choy, broccoli, kale, collard greens) on CVD incidence:
A meta-analysis (2016)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4973479/

33. Effect of highest-versus-lowest category of total cruciferous
vegetable/isothiocyanate consumption on lung cancer risk in
cohort and case-control studies (2009)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2735794/

34. Is there evidence that cruciferous vegetables can help reduce
cancer risk in people? (2012)
• Prostate cancer: Cohort studies in the Netherlands (4), United States (5),
and Europe (6) found little or no association with prostate cancer risk.
• Colorectal cancer: Cohort studies in the United States and the Netherlands
have generally found no association between cruciferous vegetable intake
and colorectal cancer risk.
• Lung cancer: Cohort studies in Europe, the Netherlands, and the United
States have had varying results
• Breast cancer: A meta-analysis of studies conducted in the United States,
Canada, Sweden, and the Netherlands found no association between
cruciferous vegetable intake and breast cancer risk
• A few studies have shown that the bioactive components of cruciferous
vegetables can have beneficial effects on biomarkers of cancer-related
processes in people. For example, one study found that indole-3-carbinol
was more effective than placebo in reducing the growth of abnormal cells
on the surface of the cervix.
https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cruciferous-vegetables-fact-sheet

35. SAFETY ISSUES
SIDE EFFECTS
PRECAUTIONS

36. Safety issues
▪ Side effects are rare when consumed in food amounts.
▪ No serious toxic effects have been reported.
▪ Kale may cause the following allergic symptoms:
▪ itchy skin.
▪ hives.
▪ mild swelling of the lips, tongue, and throat.
▪ dizziness.
▪ digestive distress.
▪ oral allergy syndrome.
▪ High concentration of vitamin K has been shown to
▪ potentiate the effect of anti-coagulants.
https://www.healthline.com/health/kale-allergy#whos-allergic

37. Can glucosinolates in kale cause hypothyroidism?
▪ Goitrin, a degradation product of glucosinolate in kale, reduces the
production of thyroid hormones such as thyroxine.
▪ However, they do not seem to alter thyroid function in humans at realistic
amounts in the diet.
https://pubmed.ncbi.nlm.nih.gov/26946249/
Thyroid

38. COMMERCIAL PRODUCTS
SOME DELICIOPUS CUISINE

39. Commercial kale products
Fresh kale Kale juice Kale chips Kale powder

40. Some delicious kale cuisne

41. Summary
▪ Kale has been called a super food because of its
nutrient and phytonutrient compositions.
▪ It is rich in potassium, calcium, vitamins A, K and C.
▪ The phytonutrients beta-caroteine, lutein, zeaxanthine,
glucosinolates, phenolic acids and flavonoids have
been shown to be beneficial for health.
▪ However, clinical studies are limited. Further research
is needed.

42. ANY QUESTION?
Other slide presentations available at:
https://www.slideshare.net/ssusera9ba27/presentations