Role of dietary phospholipids and phytosterols in protection against peptic ulceration as shown by experiments on rats

Geographically the prevalence of duodenal ulceration is related to the staple foods in the diet in regions of developing countries where the diet is stable. It is higher in regions where the diet is based on milled rice, refined wheat or maize, yams, cassava, sweet potato, or green bananas, and is lower in regions where the staple diet is based on unrefined wheat or maize, soya, certain millets or certain pulses. Experiments on rat gastric and duodenal ulcer models showed that it was the lipid fraction in staple foods from low prevalence areas that was protective against both gastric and duodenal ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs). It also promoted ulcer healing. The lipid from the pulse, Dolichos biflorus, horse gram which was highly protective was used to identify the fractions with protective activity in the lipid. The protective activity lay in the phospholipid, sterol and sterol ester fractions. In the phospholipid fraction phosphatidyl choline (lethicin) and phosphatidyl ethanolamine (cephalin) were predominant. In the sterol fraction the sub-fractions showing protective activity contained β-sitosterol, stigmasterol, and an unidentified isomer of β-sitosterol. The evidence from animal models shows that certain dietary phospholipids and phytosterols have a protective action against gastroduodenal ulceration, both singly and in combination. This supports the protective role of staple diets in areas of low duodenal ulcer prevalence and may prove to be of importance in the prevention and treatment of duodenal ulceration and management of recurrent ulcers. A combination of phospholipids and phytosterols could also play an important role in protection against ulceration due to NSAIDs.

Dietary phosphilipids and sterols protective against peptic ulceration

The prevalence of duodenal ulceration in regions of developing countries with a stable diet is related to the staple food(s) in that diet. A higher prevalence occurs in areas where the diet is principally milled rice, refined wheat or maize, yams, cassava, sweet potato or green bananas, and a lower prevalence in areas where the staple diet is based on unrefined wheat or maize, soya, certain millets or certain pulses. Experiments using animal peptic ulcer models showed that the lipid fraction in foods from the staple diets of low prevalence areas gave protection against both gastric and duodenal ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs), and also promoted healing of ulceration. The protective activity was found to lie in the phospholipid, sterol and sterol ester fractions of the lipid. Amongst individual phospholipids present in the phospholipid fraction, phosphatidyl ethanolamine (cephalin) and phosphatidyl choline (Lecithin) predominated. The sterol fraction showing activity contained β-sitosterol, stigmasterol and an unidentified isomer of β-sitosterol. The evidence shows that dietary phytosterols and phospholipids, both individually and in combination, have a protective effect on gastroduodenal mucosa. These findings may prove to be important in the prevention and management of duodenal and gastric ulceration including ulceration due to NSAIDs.

Dietary Phytosterols Protective Against Peptic Ulceration

BACKGROUND

In developing countries the prevalence of duodenal ulceration is related to the staple diet and not to the prevalence of Helicobacter pylori. Experiments using animal peptic ulcer models show that the lipid fraction in foods from the staple diets of low prevalence areas gives protection against ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs), and also promotes healing of ulceration. The lipid from the pulse Dolichos biflorus (Horse gram) was highly active and used for further investigations. Further experiments showed the phospholipids, sterol esters and sterols present in Horse gram lipid were gastroprotective. Dietary phospholipids are known to be protective, but the nature of protective sterols in staple diets is not known. The present research investigates the nature of the protective phytosterols.

METHODS

Sterol fractions were extracted from the lipid in Dolichos biflorus and tested for gastroprotection using the rat ethanol model. The fractions showing protective activity were isolated and identification of the components was investigated by Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS

The protective phytosterol fraction was shown to consist of stigmasterol, β-sitosterol and a third as yet unidentified sterol, isomeric with β-sitosterol.

CONCLUSIONS

Dietary changes, affecting the intake of protective phospholipids and phytosterols, may reduce the prevalence of duodenal ulceration in areas of high prevalence and may reduce the incidence of recurrent duodenal ulceration after healing and elimination of Helicobacter pylori infection. A combination of phospholipids and phytosterols, such as found in the lipid fraction of ulceroprotecive foods, may be of value in giving protection against the ulcerogenic effect of NSAIDs.

Precise role of H pylori in duodenal ulceration

The facts that H pylori infection is commoner in duodenal ulcer (DU) patients than in the normal population, and that eradication results in most cases being cured, have led to the belief that it causes DU. However, early cases of DU are less likely than established ones to be infected. H pylori-negative cases are usually ascribed to specific associated factors such as non-steroidal anti-inflammatory drugs (NSAIDs), Crohn’s disease, and hypergastrinaemia, but even after excluding these, several H pylori-negative cases remain and are particularly common in areas of low prevalence of H pylori infection. Moreover, this incidence of H pylori negative DU is not associated with a fall in overall DU prevalence when compared with countries with a higher H pylori prevalence. In countries with a high H pylori prevalence there are regional differences in DU prevalence, but no evidence of an overall higher prevalence of DU than in countries with a low H pylori prevalence. There is no evidence that virulence factors are predictive of clinical outcome. After healing following eradication of H pylori infection DU can still recur. Medical or surgical measures to reduce acid output can lead to long-term healing despite persistence of H pylori infection. Up to half of cases of acute DU perforation are H pylori negative. These findings lead to the conclusion that H pylori infection does not itself cause DU, but leads to resistance to healing, i.e., chronicity. This conclusion is shown not to be incompatible with the universally high prevalence of DU compared with controls.

Helicobacter pylori virulence factors in duodenal ulceration: A primary cause or a secondary infection causing chronicity

Reports from countries with a high prevalence of Helicobacter pylori (H pylori) infection do not show a proportionately high prevalence of duodenal ulceration, suggesting the possibility that H pylori cannot be a primary cause of duodenal ulceration. It has been mooted that this discrepancy might be explained by variations in the prevalence of virulence factors in different populations. The aim of this paper is to determine whether the published literature gives support to this possibility. The relevant literature was reviewed and analyzed separately for countries with a high and low prevalence of H pylori infection and virulence factors. Although virulent strains of H pylori were significantly more often present in patients with duodenal ulcer than without the disease in countries with a low prevalence of H pylori infection in the population, there was no difference in the prevalence of virulence factors between duodenal ulcer, non - ulcer dyspepsia or normal subjects in many countries, where the prevalence of both H pylori infection and of virulence factors was high. In these countries, the presence of virulence factors was not predictive the clinical outcome. To explain the association between virulence factors and duodenal ulcer in countries where H pylori prevalence is low, only two papers were found that give little support to the usual model proposed, namely that organisms with the virulence factors are more likely than those without them to initiate a duodenal ulcer. We offer an alternative hypothesis that suggests virulence factors are more likely to interfere with the healing of a previously produced ulcer. The presence of virulence factors only correlates with the prevalence of duodenal ulcer in countries where the prevalence of H pylori is low. There is very little evidence that virulence factors initiate duodenal ulceration, but they may be related to failure of the ulcer to heal.

Duodenal ulcer in South Africa: home-pounded versus milled maize

BACKGROUND

In South Africa there is suggestive evidence that home-pounded maize protects against duodenal ulceration. Therefore the purpose of the present paper was to test, in an animal model, whether oil from home-pounded maize gives protection against ulceration and whether this effect is present in commercially prepared maize oil.

METHODS

Gastric ulceration was induced in rats with topical ethanol 1 h after giving oil prepared either from fresh-pounded or from commercially treated maize. The lengths of the linear ulcers produced were measured with a planimeter and summed in each rat. Control observations were made using arachis oil (which is known not to be ulceroprotective) and horse gram lipid (which is known to be strongly ulceroprotective). Statistical comparisons were performed mainly with the Mann-Whitney U-test, but also with reference to the normal distribution. Thin-layer chromatography (TLC) was performed on the oil from fresh maize, and the fractions similarly investigated for ulceroprotective activity.

RESULTS

Fresh maize oil was strongly ulceroprotective (P = 0.0039), commercial maize oil was not (P = 0.2864). The active ingredient in the fresh maize oil was located in the fraction near the solvent front.

CONCLUSION

These findings support the hypothesis that home-pounded maize protects against duodenal ulceration.

Duodenal gastric metaplasia and Helicobacter pylori infection in high and low duodenal ulcer-prevalent areas in India

BACKGROUND

Previous reports, based on surgery, showed duodenal ulcer (DU) to be more common in the rice-eating areas of southern India than in the northern wheat-eating areas.

AIMS

Does this difference persist? Can it be explained by risk factors other than diet?

METHODS

A total of 20 053 records from patients undergoing endoscopy for dyspepsia, and 590 endoscopy patients from two northern and two southern centers in India were studied prospectively. Records were scrutinized to determine the relative incidence of DU and non-ulcer dyspepsia in wheat- and rice-eating areas. Age, sex, length of history, smoking and medication were recorded. Three antral biopsies and one from each duodenal quadrant were taken. A rapid urease test was carried out on one of the antral biopsies; the others were examined for Helicobacter pylori, gastritis, duodenitis and duodenal gastric metaplasia.

RESULTS

The difference in diet-associated prevalence persisted. No differences in smoking, Helicobacter pylori infection or duodenal gastric metaplasia were found between the two regions, but all three were more common in DU than in non-ulcer dyspeptic patients from both dietary areas.

CONCLUSIONS

The dietary differences between the regions remain the only factor to account for the differences in DU prevalence. A strong interrelationship between duodenal gastric metaplasia and cigarette smoking is demonstrated.

Duodenal ulcer prevalence: research into the nature of possible protective dietary lipids

The varying geographical prevalence of duodenal ulceration has suggested a relationship to staple diet. Previous experiments on animal peptic ulcer models showed that certain foods, particularly the lipid fraction, are ulceroprotective. This paper reports experiments on animal models further to investigate the nature of the protective substances in the most active lipid, that of horse gram. The free fatty acids and triglycerides, sterols, sterol esters and phospholipids from horse gram were extracted and tested for protective activity on rat peptic ulcer models: the pyloric ligation model which is chronic, involving 14 days pre-feeding, and two acute models using ethanol or cysteamine to induce ulceration. The results showed that sterol esters, but not sterols, were protective in the pyloric ligation model. Sterols were protective in the acute models using ethanol-induced and cysteamine-induced ulceration. Phospholipids were protective in both types of model. The free fatty acids and triglycerides gave no protection using the pyloric ligation model. The presence of sterols, sterol esters and phospholipids in the lipid fraction of foods in staple diets may account for the low prevalence of duodenal ulcer in certain geographical areas, despite a uniformly high prevalence of Helicobacter pylori infection.

Possible absence of Helicobacter pylori in the early stages of duodenal ulceration

BACKGROUND

Helicobacter pylori is thought to be a cause of duodenal ulceration, but there is some evidence that it is found less often in early than in later disease.

AIM

To assess the presence of H. pylori in patients undergoing endoscopy for dyspepsia, with respect to their duration of symptoms.

DESIGN

Retrospective case note review.

METHODS

Patients were categorized as having a history greater or less than 6 months, and as H. pylori-positive or -negative, using biopsy rapid urease, culture and PCR tests.

RESULTS

Thirty-two duodenal ulcer patients with a history >6 months were all H. pylori-positive according to the PCR test; the five with a shorter history were H. pylori-negative. No patient H. pylori-negative by PCR was positive by the other tests.

DISCUSSION

H. pylori was (at least) less commonly present before 6 months. It is possible that H. pylori, although nearly always present after 6 months, is not present at the onset of the disease. Confirmation of this finding would imply that infection with the organism is not the cause of duodenal ulceration, but a factor producing recurrence and chronicity.

Dietary factors in relation to the distribution of duodenal ulcer in India as assessed by studies in rats

BACKGROUND

The prevalence of duodenal ulcer is less in the northern wheat-eating regions of India and China than in the southern rice-eating areas.

METHODS AND RESULTS

Experiments were conducted on rat peptic ulcer models in which controls were fed on either known ulcerogenic rice or rice plus tapioca diets or on non-ulcerogenic stock diet. By using an ulcerogenic diet and pyloric ligation, unrefined wheat, wheat bran and their respective oils were protective against ulceration. Refined wheat, wheat germ and its oil were not protective. Freshly milled rice and unmilled rice were protective, but stored rice bran and its oil increased the ulceration. Fresh rice bran oil was not ulcerogenic, but on storage, it became ulcerogenic. By using stock diet and alcohol-induced ulceration, the findings with whole wheat oil, wheat bran and wheat germ oil were confirmed. Rats fed on the stock diet subjected to pyloric ligation developed ulcers following intragastric injection of stored rice bran oil. This ulcerogenicity was counteracted by whole wheat oil.

CONCLUSION

These results suggest that the factor of diet may well explain the regional differences in the prevalence of duodenal ulceration between North and South India and China where other etiologic factors are similar.

Duodenal ulcer prevalence: experimental evidence for the possible role of dietary lipids

BACKGROUND AND AIMS

Mapping the geographical distribution of duodenal ulcer in relation to staple diets, and experiments on animal peptic ulcer models suggested that the lipid fraction in certain foodstuffs had a protective effect which was most marked in the lipid obtained from Horse gram (Dolichos biflorus). Lipid obtained from stored polished rice or rice bran was ulcerogenic. Further animal experiments were designed to investigate the protective and healing effects of Horse gram lipid (HGL) against peptic ulceration.

METHODS

Three effects were investigated in rats: (i) the protective effect of HGL on peptic ulceration produced by using pyloric ligation in combination with South Indian diet or rice bran oil, or by cysteamine, alcohol or aspirin; (ii) the effect of HGL on mast cell degranulation in response to pyloric ligation and rice bran oil; and (iii) the healing effect of HGL on acute gastric ulceration produced by alcohol, on chronic gastric ulceration produced by topical acetic acid or on chronic duodenal ulcer following cysteamine.

RESULTS

Horse gram lipid was shown to be protective and to promote ulcer healing in all the models used. Mast cell degranulation was inhibited.

CONCLUSION

The experiments confirm the presence of a lipid in certain staple foods that have protective and healing properties in experimental peptic ulcer animal models. The differences in the prevalence of duodenal ulceration between different regions in some developing countries with a high prevalence of Helicobacter pylori infection might be explained by the presence or absence of protective lipids or ulcerogenic factors in the staple diet.

Post-gastrectomy patients need to be followed up for 20-30 years

AIM: To investigate the incidence and management of nutritional deficiencies following a gastrectomy.

METHODS: A gastrectomy population of 227 patients in London was followed up for 30 years after operation to detect and treat nutritional deficiencies.

RESULTS: By the end of the first decade iron deficiency was the commonest problem. Vitamin B₁₂ deficiency became more important in the second decade. During the third decade both reached equal prevalence, being found in some 90% of the female and 70% of the male residual population. Vitamin D deficiency was a lesser problem, reaching its climax in the second decade. Overall, all women fared worse than men.

CONCLUSION: The importance of long-term follow-up of gastrect omy patients foriron, Vitamin B₁₂ and Vitamin D deficiencies is emphasised.

Is Helicobacter pylori the primary cause of duodenal ulceration?

Helicobacter pylori infection may not be the primary cause of duodenal ulceration in cases not associated with non-steroidal anti-inflammatory drugs, but may be a secondary complication. In developing countries with a uniformly high prevalence of H. pylori infection there are marked regional differences in the prevalence of duodenal ulcer (DU). In some countries, especially those with a low prevalence of H. pylori, 30-40% or more patients with DU may be H. pylori negative. The absence of H. pylori infection in early cases of DU is also reported. In DU patients with antral H. pylori infection, duodenal colonization by H. pylori may often be absent. After complete H. pylori eradication, recurrence of DU within 6 months in some reports is as high as 20%. The evidence suggests that high acidity and reduced duodenal mucosal resistance remain the primary causes of DU and that H. pylori infection, when present, results in chronicity. Reduced mucosal resistance results in duodenal gastric metaplasia which permits colonization of the duodenum with H. pylori from the antrum. Therefore, whatever causes reduced mucosal resistance may be the primary factor and evidence suggests that this cause may be diet related. This would explain the enigma of regional variations in DU prevalence unrelated to H. pylori prevalence.

A review of postgastrectomy bone disease

Postgastrectomy bone disease was a term devised to describe the metabolic disorders of bone which may follow a gastrectomy operation. Although the use of this operation has declined drastically in recent years, this metabolic bone disorder is still with us and may escape and confuse the unwary. These disorders may take the form of osteomalacia, osteoporosis in excess of normal ageing, or a combination of both. For screening purposes, regular estimations of plasma alkaline phosphatase levels identify patients who may be developing osteomalacia which can then be treated with calcium and vitamin D supplements. Numerically, osteoporosis in excess of ageing is a bigger problem and its prevention and treatment is at present unsatisfactory. Screening procedures for osteoporosis are reviewed, including the more recent methods of bone mineral density assessment. Osteopenia or demineralization occurs in both osteomalacia and osteoporosis therefore osteomalacia must be excluded before attributing any loss to osteoporosis. The present situation with regards to the prevention and treatment of osteoporosis is also reviewed.

Duodenal ulcer in China

The author visited China in 1981 and 1984 and obtained data comparing the incidence of duodenal ulcer in the rice eating districts of the south with the incidence in the wheat, maize and millet eating areas of the north. The evidence suggested a higher prevalence of duodenal ulcer in the rice eating areas than in the wheat eating areas, and a low prevalence in association with millet eating. However, the differences were less marked than between similar rice and wheat eating areas of India. It is suggested that the lower prevalence of duodenal ulcer in the wheat eating areas of north India compared with the rice eating areas of south India may be due in part to the mucosal protective effect of wheat bran in the unrefined wheat that is used in making chappatis. In China white refined flour is used in the making of steamed bread with the loss of any protective effect of wheat bran.

Postgastrectomy osteoporosis

Osteoporosis is a recognized complication following partial gastrectomy and is more common than osteomalacia. Recent improvements in the measurement of bone mineral status (dual energy X-ray absorptiometry, DEXA) have assisted in measuring osteoporosis. Sixteen men who had undergone gastrectomy more than 30 years previously were examined. This study reports the effect of calcium supplementation in six patients in whom osteomalacia had been excluded and who showed abnormally low bone mineral densities on DEXA scanning. Calcium supplementation for 6 months (microcrystalline hydroxyapatite, Ossopan 8-32 g per day) produced no significant advantage for the treatment group at any site measured.

A gastrectomy population: 25-30 years on

Prior to 1960 a Polya gastrectomy was the most frequent operation for duodenal ulcer. The majority of these patients now have reached the age of sixty or older. A prospective longitudinal study of a cohort of patients who underwent gastrectomy between 1955 and 1960 was undertaken. Twenty five to thirty years later the study has revealed the extent of the nutritional problems that may arise with the passage of time and shows that these numerically far outweigh the mechanical post-gastrectomy syndromes and weight loss which tended to dominate the earlier post-gastrectomy scene. By the end of the first decade, iron deficiency was the commonest nutritional problem. Vitamin B12 deficiency assumed more importance in the second decade. During the third decade both reached equal prevalence, being found in some 90% of the female and 70% of the male residual population. Vitamin D deficiency and early osteomalacia was a lesser problem, reaching its climax in the second decade. Evidence suggested a high incidence of osteoporosis and this requires further investigation. Overall, women fared worse than men with a higher and earlier incidence of iron deficiency, particularly in the pre-menopausal group. This study emphasizes the increasing need for regular screening of post-gastrectomy patients to detect early iron, vitamin B12 and vitamin D deficiencies as patients grow older.