Editorials
Copyright ©The Author(s) 1998. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 15, 1998; 4(6): 469-470
Published online Dec 15, 1998. doi: 10.3748/wjg.v4.i6.469
Phytochemical malabsorption: clinical significance
Mark L Wahlqvist, Naiyana Wattanapenpaiboon
Mark L Wahlqvist, Naiyana Wattanapenpaiboon, Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria 3168, Australia
Author contributions: All authors contributed equally to the work.
Correspondence to: Professor Mark L Wahlqvist, Department of Medicine, Monash University, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia. mark.wahlqvist@med.monash.edu.au
Telephone: +61-613-95505525 Fax: +61-613-95505437
Received: October 20, 1998
Revised: November 15, 1998
Accepted: December 5, 1998
Published online: December 15, 1998

Abstract
Key Words: phytochemicals, vitamins, minerals, gastrointestinal malabsorption



CLINICAL SIGNIFICANCE OF PHYTOCHEMICALS

Until recent years, nutritionists have focused primarily on macronutrients and micronutrients in foods. Appreciation is now increasing that many food components, of plant origin (‘phytochemicals’) in particular, have the potential to affect human biology. Phytochemicals by definition are important components of food that may not be essential in the classical sense, and may not even be required to sustain life as vitamins or minerals do, but are likely to contribute to optimal health.

A problem in considering the place of phytochemicals in human health is that they are numerous, alongside a few known essential nutrients. Therefore, their net interactive effect ultimately requires a study of food itself and food patterns, so that food component intake may need to be subject to sophisticated mathematical modelling. However, the advant of advanced informatics may help resolve this dilemma.

Examples of phytochemicals, along with some of their food sources are listed according to their chemical structure in Table 1. The possible roles of these phytochemicals in the treatment of health conditions are rapidly unfolding[1], and the use of an index of preferred phytochemical intake has been suggested[2]. Yet limited information is available on the bioavailability of most of these compounds. With complex factors influencing the absorption and transport of phytochemicals, it is not easy to predict their bioavailability, let alone consider the implications of gastrointestinal malabsorption.

Table 1 Selected phytochemicals and their possible roles in health[3].
PhytochemicalsSome important food sourcesPossible roles in health
CarctenoidsOrange pigmented and greenAntioxidants
leafy vegetables, e.g.Antimutagen
carrots,Anticarcinogen
tomatoes, spinachImmuno-enhancement
Flavonoids,Green and yellow leafyAntioxidants
isoflavonoidsvegetables, e.g. parsley,Anticarcinogen
and saponinscelery, soy bean and soyOestrogenic
productsImmuno-modulating
PolyphenolsCranberry, raspberries,Antioxidants
blackberriesAntibacterial
Rosemary, oregano, thymeReduce urinary tract infection
CalechinsGreen teaAntimutagen
Anticarcinogen
Anticariogen
Allyl thiosulfinatesGarlic, onions, leeksAnticarcinogen
Antibacterial
Cholesterol lowering
IsolhiocyanatesCruciferous vegetables, e.g.Antimutagen
and indolesbroccoli, cabbage
Phytosterols,Pumpkin seedsReduce symptoms of prostate
e.g. β-sitosterolenlargement
BIOLOGICAL OCCURRENCE AND RELEVANCE OF PHYTOCHEMICALS

The presence and the physiological concentration of phytochemicals in biological tissues or fluids, especially blood and urine, create the opportunity for biomarkers of the consumption of phytochemical-containing foods[4-6] (Table 2). Equally, measurements of phytochemicals reflect bioavailability, including absorption.

Table 2 Occurrence of phytochemicals in human blood and tissues.
PhytochemicalsWhere can we find them in the body
CarotenoidsSerum (five major carotenoids)
Lutein/zeaxanthinSkin
β-cryptoxanthinAdipose tissues
LycopeneLens and macula (lutein/zeaxanthin)
α-caroteneVarious tissues like prostate (lycopene)
β-carotene
FlavonoidsSerum
Quercetin, kaempferolUrine
IsoflavcnesSerum
Geristein, daidzeinUrine
Catechins eplgallo-catechin gallateSerum
Allyl thiosulfinatesBlood, serum, red blood cells
organosulfidesAdipose tissue
vinyl dithiinsLiver
Kidney
Breath
TocotrienolsSikin

For the moment, the presence of phytochemicals in tissues, is presumptive evidence of functional significance, especially where there is a plausible mechonism of action (e.g. carotenoids as antioxidants for serum lipoproteins). Observations like this generate a number of exciting hypotheses for further research.

CLINICAL SIGNIFICANCE OF PHYTOCHEMICAL MALABSORPTION

Given the putative health benefits of phytochemicals, gastrointestinal malabsorption may well contribute to a loss of their protective effects. This could result in a number of clinical disorders which could be referred to as ‘phytochemical deficiency disorders’[1]. Candidate disorders are:

a. The menopause as a ‘phytoestrogen deficiency disorder’[7]

b. Cardiovascular disease because of the role of certain phytochemicals as antioxidants, others as are regulators of endothelial function and others as modulators of myocardial function

c. Colorectal cancer in relation to a range of phytochemical intakes from various fruits and vegetables, and whole grain cereals[8]

d. Prostatic disease in relation to lycopene and isoflavones[9,10]

e. Maculopathy on account of the contribution to macular function of lutein and zeaxanthin[11]

Two cases of short bowel syndrome where carotenoids were undetectable in serum illustrate the potential for these orders (Case reports 1 and 2). In each case, it was possible to increase serum carotenoid concentrations by vegetable juice supplements.

Case report 1. Mrs BW (b. 1956)

Vaginal cancer (1990) treated with radiotherapy

Rectovaginal fistula → colostomy (1992)

Short bowel syndrome (1995) (Table 3)

Table 3 Not available.
Vegetable juice/soupNoYes
Serum concentration (nmol/L)Reference rangeJan 96May 97
Lutein/zeaxanthin80-850102202
β-cryptoxanthin175-1350Not detectable12
Lycopene69-650Not detectable33
α-carotene15-300Not detectableNot detectable
β-carotene45-900Not detectable93

Case report 2. Mrs CM (b. 1956)

Severe road traffic accident (1976) → ruptured bowel, bowel resections

Short bowel syndrome (Table 4)

Table 4 Not available.
V-8ceTM (glass/day)01 × 21 × 1
Serum concentration (nmol/L)Reference rangeNov 95May 96Nov 96
Lutein/zeaxanthin80-850Not detectable24317
β-crytoxanthin175-1350Not detectable18Not detectable
Lycopene69-650Not detectable3211
α-carotene15-300Not detectableNot detectableNot detectable
β-carotene45-900Not detectable108
CONCLUSIONS

Witn arnergent evidence for physiological roles of phytochemicals and for their potential for disease protection, the use of foods, which are good phytochemical sources, to prevent and manage disease will be encouraged. The malabsorption of phytochemicals is likely to be one of many pathways to so-called “phytochemical deficiency disorders”.

References
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