Assessing the impact of chemical pollution on benthic invertebrates from three different European rivers using a weight-of-evidence approach.

The aim of this study was to combine different lines of evidence on the impact of chemical pollution on benthic invertebrate communities in three European river basins (Elbe, Scheldt, and Llobregat). The study integrates chemical analyses, a battery of different sediment toxicity tests, and field data from soft-sediment meio- and macrobenthic fauna within a sediment-quality triad in which chironomids, oligochaetes, and nematodes are identified on the species level. The use of TU (toxic units) and msPAF (multi-substance potentially affected fraction) in an approach assessing the chemical impact as well as the integration of sediment toxicity tests with bacteria (Vibrio fischeri), benthic invertebrates (Caenorhabditis elegans, Potamopyrgus antipodarum, Lumbriculus variegatus, Chironomus riparius), and fish embryos (Danio rerio), together with univariate and non-parametric multivariate statistical analyses of the biological data revealed significant differences between unpolluted and polluted sites in all three river basins. To combine the different results obtained in the sediment-quality triad, a scoring system was successfully developed based on a simple algorithm. This system provides an easily understandable scheme for non-experts among decision makers and water managers.

Toxicity assessment of sediments from three European river basins using a sediment contact test battery.

The toxicity of four polluted sediments and their corresponding reference sediments from three European river basins were investigated using a battery of six sediment contact tests representing three different trophic levels. The tests included were chronic tests with the oligochaete Lumbriculus variegatus, the nematode Caenorhabditis elegans and the mudsnail Potamopyrgus antipodarum, a sub-chronic test with the midge Chironomus riparius, an early life stage test with the zebra fish Danio rerio, and an acute test with the luminescent bacterium Vibrio fischeri. The endpoints, namely survival, growth, reproduction, embryo development and light inhibition, differed between tests. The measured effects were compared to sediment contamination translated into toxic units (TU) on the basis of acute toxicity to Daphnia magna and Pimephales promelas, and multi-substance Potentially Affected Fractions of species (msPAF) as an estimate for expected community effects. The test battery could clearly detect toxicity of the polluted sediments with test-specific responses to the different sediments. The msPAF and TU-based toxicity estimations confirmed the results of the biotests by predicting a higher toxic risk for the polluted sediments compared to the corresponding reference sediments, but partly having a different emphasis from the biotests. The results demonstrate differences in the sensitivities of species and emphasize the need for data on multiple species, when estimating the effects of sediment pollution on the benthic community.

Arsenic in drinking water wells on the Bolivian high plain: Field monitoring and effect of salinity on removal efficiency of iron-oxides-containing filters.

In the rural areas around Oruro (Bolivia), untreated groundwater is used directly as drinking water. This research aimed to evaluate the general drinking water quality, with focus on arsenic (As) concentrations, based on analysis of 67 samples from about 16 communities of the Oruro district. Subsequently a filter using Iron Oxide Coated Sand (IOCS) and a filter using a Composite Iron Matrix (CIM) were tested for their arsenic removal capacity using synthetic water mimicking real groundwater. Heavy metal concentrations in the sampled drinking water barely exceeded WHO guidelines. Arsenic concentrations reached values up to 964 µ g L⁻¹ and exceeded the current WHO provisional guideline value of 10 µ g L⁻¹ in more than 50% of the sampled wells. The WHO guideline of 250 mg L⁻¹ for chloride and sulphate was also exceeded in more than a third of the samples, indicating high salinity in the drinking waters. Synthetic drinking water could be treated effectively by the IOCS- and CIM-based filters reducing As to concentrations lower than 10 µ g L⁻¹. High levels of chloride and sulphate did not influence As removal efficiency. However, phosphate concentrations in the range from 4 to 24 mg L⁻¹ drastically decreased removal efficiency of the IOCS-based filter but had no effects on removal efficiency of the CIM-based filter. Results of this study can be used as a base for further testing and practical implementation of drinking water purification in the Oruro region.

Influence of tidal regime on the distribution of trace metals in a contaminated tidal freshwater marsh soil colonized with common reed (Phragmites australis).

A historical input of trace metals into tidal marshes fringing the river Scheldt may be a cause for concern. Nevertheless, the specific physicochemical form, rather than the total concentration, determines the ecotoxicological risk of metals in the soil. In this study the effect of tidal regime on the distribution of trace metals in different compartments of the soil was investigated. As, Cd, Cu and Zn concentrations in sediment, pore water and in roots were determined along a depth profile. Total sediment metal concentrations were similar at different sites, reflecting pollution history. Pore water metal concentrations were generally higher under less flooded conditions (mean is (2.32+/-0.08)x10(-3) mg Cd L(-1) and (1.53+/-0.03) x 10(-3) mg Cd L(-1)). Metal concentrations associated with roots (mean is 202.47+/-2.83 mg Cd kg(-1) and 69.39+/-0.99 mg Cd kg(-1)) were up to 10 times higher than sediment (mean is 20.48+/-0.19 mg Cd kg(-1) and 20.42+/-0.21 mg Cd kg(-1)) metal concentrations and higher under dryer conditions. Despite high metal concentrations associated with roots, the major part of the metals in the marsh soil is still associated with the sediment as the overall biomass of roots is small compared to the sediment.

Effect of fortified spread on homocysteine concentration in apparently healthy volunteers.

OBJECTIVE: To determine the effect of folic acid, vitamin B(6) and B(12) fortified spreads on the blood concentrations of these vitamins and homocysteine. DESIGN AND SETTING: A 6-week randomized, double-blinded, placebo-controlled, parallel trial carried out in a clinical research center. SUBJECTS: One hundred and fifty healthy volunteers (50% males). INTERVENTIONS: For 6 weeks, the subjects consumed the test spreads (20 g/day): containing per 20 g (1) 200 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6), or (2) 400 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6) or (3) no B-vitamins (control spread). RESULTS: The B-vitamin status increased on using the test spreads, with the largest effect on the serum folate concentration: 48% in men and 58% in women on spread 1 and 92 and 146%, respectively, on spread 2 (P-values all <0.05). The plasma homocysteine decreased in the groups treated with the fortified spreads as compared to the control group. Average decreases were for males: 0.7+/-1.5 micromol/l (6.8%) on spread 1 and 1.7+/-1.7 micromol/l (17.6%) on spread 2 and for females: 1.4+/-1.2 micromol/l (14.2%) and 2.4+/-2.0 micromol/l (23.3%), respectively (P-values all <0.05). CONCLUSIONS: Consumption of a spread fortified with folic acid, vitamin B(6) and vitamin B(12) for 6 weeks significantly increases the blood concentrations of these vitamins and significantly decreases the plasma concentration of homocysteine. Fortified staple foods like spreads can contribute to the lowering of homocysteine concentrations.

Acute absorption of folic acid from a fortified low-fat spread.

OBJECTIVE: To explore the feasibility of low-fat spreads as vehicles for folic acid (FA) fortification by determining the acute absorption of FA from a fortified spread. DESIGN: Double blind, crossover study to test each of the following treatments administered at 1-weekly intervals: (A) 20 g low-fat (40%) spread fortified with 200 microg FA and a placebo tablet; (B) 20 g low-fat placebo spread and a 200 microg FA tablet; (C) 20 g low-fat placebo spread and a placebo tablet. SUBJECTS: A total of 13 male volunteers, aged 31.8+/-13.2 y. MAIN OUTCOME MEASURES: Plasma total folate concentrations, measured before and up to 10 h after each treatment (n=10 samples per treatment). RESULTS: Plasma folate concentrations were significantly increased compared with baseline values 1 h after administration of the FA tablet, and 1.5 h after the FA spread, and remained significantly higher than the baseline values for up to 7 h after both treatments. The maximum plasma folate response (R(max)), corrected for baseline values and 'placebo response', was established between 1 and 3 h postprandially in response to both FA spread and FA tablet, and no significant difference in R(max) was found between the two treatments (13.4 vs 14.4 nmol/l, P=0.9). The acute absorption of FA from fortified spread relative to that from the tablet, calculated on the basis of area under the plasma folate response curve, was 67% (P=0.04). CONCLUSION: The absorption of FA from fortified low-fat spread, although lower than from a tablet, is effective. These results suggest that low-fat spreads, typically associated with fat-soluble vitamin fortification, may also be considered feasible as vehicles for FA fortification.

Conjugated linoleic acid isomers have differential effects on triglyceride secretion in Hep G2 cells.

The effect of different conjugated linoleic acid (CLA) isomers (trans-10,cis-12 (t10,c12)-CLA and cis-9,trans-11 (c9,t11)-CLA), compared with oleic acid (OA) and linoleic acid (LA), on hepatic lipid synthesis and secretion were investigated in Hep G2 cells. The cells were incubated in a medium containing 1 mmol/l fatty acid-bovine serum albumin (BSA) complex for 5 h, with BSA alone as control. [(3)H]Glycerol and [(14)C]acetate were used to monitor lipid synthesis and secretion. The results show that cellular uptake rates of these fatty acids were similar. Incubation with OA, t10,c12-CLA, c9,t11-CLA and LA resulted in 6-, 4-, 2- and 1.8-fold increases in intracellular [(3)H]triglyceride ([(3)H]TG) compared with incubation with BSA alone. OA, LA and c9,t11-CLA increased [(3)H]TG secretion 3.6-, 2.5- and 1.2-fold above the control, whereas t10,c12-CLA markedly suppressed the secretion of [(3)H]TG. Hepatic secretion of TG mass increased 3.5-, 3.3-, 2.7- and 1.5-fold in the cells incubated with OA, LA, c9,t11-CLA and t10,c12-CLA, respectively. Since the secreted TG is mainly contained in very low density lipoproteins (VLDL), the decreased ([(3)H])TG secretion by t10,c12-CLA reflects a diminished secretion of VLDL. With respect to cholesterol synthesis OA was more effective in stimulating the incorporation of [(14)C]acetate into cellular total cholesterol followed in descending order by LA, c9,t11-CLA and t10,c12-CLA. In conclusion, the biological properties of 18-carbon fatty acids are clearly influenced by both the number and (geometric) positions of their double bonds. Furthermore t10,c12-CLA is more effective than c9,t11-CLA on suppressing hepatic TG secretion in vitro.

Bone scintigraphy and the added value of SPECT (single photon emission tomography) in detecting skeletal lesions.

Skeletal metastases are one of the major clinical problems for the oncologist. Over the last several decades bone scintigraphy has been used extensively in detecting bone involvement since it can provide information about disease location, prognosis and the effectiveness of treatment. Bone scan offers the advantage of total body examination, and images bone lesions earlier than other techniques. In this paper the main clinical problems related to the most common applications of bone scan in breast, prostate, lung cancer and other tumours are discussed. The experience carried out at the National Cancer Institute of Milan by using bone SPECT to detect single bone metastases is reported. One hundred and eighteen patients with bone metastases (from different tumour types: breast, lung, prostate, lymphomas, etc.) were studied by planar scintigraphy, SPECT and other radiological modalities (CT, MRI or X-rays). The overall performances of bone SPECT were sensitivity: 90.5% (19/21), specificity 92.8% (90/97), positive predictive value 73% (19/26), negative predictive value 97.8% (90/92), accuracy 92.4% (109/118). Considering breast cancer, the most frequent pathology in our series, and the lumbar spinal tract, the most common skeletal segment involved, the figures of merit of SPECT were: sensitivity 100% (4/4), specificity 95.3% (41/43), positive predictive value 66.7% (4/6), negative predictive value 100% (41/41), accuracy 95.7% (45/47). In conclusion bone SPECT showed very good performances, in particular improving the predictive value of planar scan in the diagnosis of vertebral metastases.

Nuclear medicine imaging of neuroendocrine tumours.

Different tracers have been proposed in nuclear medicine to visualize neuroendocrine tumours: the majority are based on specific uptake mechanisms while some are aspecific. Among the most important gamma-emitting tracers, radiolabelled metaiodobenzylguanidine (123I or 121I-MIBG) and 111In-pentetreotide should be mentioned. In particular. good results can be obtained with 111In-pentetreotide scanning, which visualizes more than 70% of all neuroendocrine tumours and in some indications, as in gastro-entero-pancreatic (GEP) tumours, has a diagnostic sensitivity superior to that of conventional radiological imaging. Radiolabelled monoclonal antibodies have at present only a storical value, while a series of new peptides represent interesting subjects in areas currently being regarded. Positron emission tomography (PET) is a successful modality to detect cancer and recent years, has demonstrated a great diagnostic value in a large series of tumour types. 18F-deoxyglucose (FDG)-PET has also been used to diagnose tumours of neuroendocrine origin. Even if 18F-FDG has been successfully and widely employed in oncology, it has not demostrated a significant uptake in well differentiated neuroendocrine tissues. On the contrary, other positron emitter tracers seem to be more promising. A serotonin precursor 5-hydroxytryptophan (5-HTP) labelled with 11C has shown an increased uptake in carcinoids. This uptake seems to be selective and some clinical evidence has demonstrated that it allows the detection of more lesions with PET than with CT or octreotide scintigraphy. Another radiopharmaceutical in development for PET is 11C L-DOPA, which seems to be useful in visualizing endocrine pancreatic tumours. This Review summarizes the potential of several nuclear medicine techniques in the diagnosis of neuroendocrine tumours and stresses the renewed role of nuclear -medicine in the management of this disease.

Possible beneficial effect of fish and fish n-3 polyunsaturated fatty acids in breast and colorectal cancer.

Breast and colorectal cancer are main causes of death in industrialized countries. In these cancers dietary factors appear to play beneficial or adverse roles. One of the possible beneficial factors may be fish intake or the n-3 polyunsaturated fatty acids from fish, as found in epidemiological and clinical studies. In population studies, high intake of fish during many years is associated with reduced risks of breast and colorectal cancer. Prospective and case-control studies either do not show an association between fish intake and cancer risks or show reduced risks at high fish intakes. In these studies, fish consumption may have been too low or may not reflect fish consumption over a longer period. In population, case-control, and prospective studies, fish and fish n-3 polyunsaturated fatty acids were not found to increase cancer risks. Clinical studies on markers of colorectal cancer indicate that fish n-3 polyunsaturated fatty acids may reduce cancer risk. In several studies in which the effect of fish consumption on cancer risk was investigated, meat and meat products were positively related to cancer risk, suggesting that cancer risks might be reduced more effectively when meat and meat products in meals are replaced by fish. In conclusion, the existing knowledge suggests that an increase in the consumption of fish and fish n-3 polyunsaturated fatty acids in industrialized countries may contribute to lower breast and colorectal cancer risks.

Effects of conjugated linoleic acid (CLA) isomers on lipid levels and peroxisome proliferation in the hamster.

Effects of the conjugated linoleic acid (CLA) isomers cis-9, trans-11 (c9,t11 CLA) and trans-10, cis-12 (t10,c12 CLA) on lipid metabolism and markers of peroxisome proliferation were investigated in hamsters fed on purified diets containing 30% energy as fat and 0.1 g cholesterol/kg for 8 weeks. Four groups (n 32 each) received diets without CLA (control), with a mixture of equal amounts of c9,t11 and t10,c12 CLA (CLA mix), with c9,t11 CLA, and with t10,c12 CLA. The total amount of CLA isomers was 1.5% energy of 6.6g/ kg diet. CLA was incorporated into glycerides and exchanged for linoleic acid in the diet. Compared with the control, the CLA mix and t10,c12 CLA decreased fasting values of LDL- (21 and 18% respectively) and HDL-cholesterol (8 and 11%), increased VLDL-triacylglycerol (80 and 61%, and decreased epididymal fat pad weights (9 and 16%), whereas c9,t11 CLA had no significant effects. All CLA preparations increased liver weight, but not liver lipids. However, the increase in liver weight was much less in the c9,t11 CLA group (8%) than in the other two groups (25%) and might have been caused by the small amount of t10,c12 CLA present in the c9,t11 CLA preparation. Liver histology revealed that increased weight was due to hypertrophy. Markers of peroxisome proliferation, such as cyanide-insensitive palmitoyl CoA oxidase (EC 1.3.3.6) and carnitine acetyl transferase (EC 2.3.1.7) activities, were not increased by CLA. Both c9,t11 CLA and t10,c12 CLA were incorporated into phospholipids and triacylglycerols, but t10,c12 CLA only about half as much as c9,t11 CLA. In addition, linoleic acid and linolenic acid concentrations were lower in lipids of the t10,c12 CLA group compared with the c9,t11 CLA group. These data suggest that t10,c12 CLA stimulated the oxidation of all C18 polyunsaturated fatty acids. The results indicate that the t10,c12 CLA isomer, and not the so-called natural CLA isomer (c9,t11), is the active isomer affecting lipid levels in hamsters.

Health aspects of fish and n-3 polyunsaturated fatty acids from plant and marine origin.

An expert workshop reviewed the health effects of n-3 polyunsaturated fatty acids (PUFA), and came to the following conclusions. 1. Consumption of fish may reduce the risk of coronary heart disease (CHD). People at risk for CHD are therefore advised to eat fish once a week. The n-3 PUFA in fish are probably the active agents. People who do not eat fish should consider obtaining 200 mg of very long chain n-3 PUFA daily from other sources. 2. Marine n-3 PUFA somewhat alleviate the symptoms of rheumatoid arthritis. 3. There is incomplete but growing evidence that consumption of the plant n-3 PUFA, alpha-linolenic acid, reduces the risk of CHD. An intake of 2 g/d or 1% of energy of alpha-linolenic acid appears prudent. 4. The ratio of total n-3 over n-6 PUFA (linoleic acid) is not useful for characterising foods or diets because plant and marine n-3 PUFA show different effects, and because a decrease in n-6 PUFA intake does not produce the same effects as an increase in n-3 PUFA intake. Separate recommendations for alpha-linolenic acid, marine n-3 PUFA and linoleic acid are preferred.

Influence of dietary retrograded starch on the metabolism of neutral steroids and bile acids in rats.

Diets enriched in retrograded amylose (RS3) have been shown to lower serum cholesterol concentrations in rats. The possibility was tested that this hypocholesterolaemic effect of RS3 is caused by an increase in excretion of neutral steroids and/or bile acids. Six groups of ten rats were fed on purified diets containing either 12 or 140 g RS3/kg solid ingredients with and without added cholesterol (5g/kg). Low-RS3 diets, with and without added cholesterol, to which the bile-acid-binding resin cholestyramine (20 g/kg) was added, were used as reference. The high-RS3 diets v. the low-RS3 diets tended to reduce the increase in the total serum cholesterol concentration during the course of the experiment (P = 0.067), decreased serum triacylglycerol concentrations, raised total neutral steroids and total bile acids in caecal contents and faecal excretion of total bile acids, but lowered faecal excretion of neutral steroids. In addition, the serum concentration of total 3 alpha-bile acids was markedly raised by the high-RS3 diets. The high-RS3 diets raised the faecal excretion of lithocholic and muricholic acids, but lowered that of hyodeoxycholic acid, and increased the caecal amounts of lithocholic, ursodeoxycholic, beta-muricholic and omega-muricholic acids. Apart from the stimulation of faecal bile acids excretion, the effects of cholestyramine on bile acid metabolism differed at various points from those of RS3. Cholesterol feeding had predictable effects on cholesterol metabolism and led to greater elevating effects of RS3 on the faecal and caecal amounts of muricholic acids. The results suggest that the serum-cholesterol-lowering effect of high-RS3 diets may be explained by an increased influx of neutral steroids and bile acids into the caecum, and increased faecal excretion of bile acids, and/or by an altered intestinal bile acid profile.

Both raw and retrograded starch decrease serum triacylglycerol concentration and fat accretion in the rat.

Male Wistar rats were meal-fed on diets containing various amounts of resistant starch in the form of raw starch (either amylomaize starch, potato starch or modified high-amylose starch) or retrograded starch (prepared from each of the starches) for 6 weeks. Two diets containing normal maize starch were fed as diets poor in resistant starch. Energy absorption (energy consumption minus faecal energy loss), growth, weight of the epididymal fat pads, serum total cholesterol and triacylglycerol concentrations and a number of intestinal and faecal variables were determined. The resistant starches affected all the variables determined except the serum total cholesterol concentration. Relationships were found between energy absorption and both growth and the weight of the fat pads, and between the weight of the fat pads and both the serum triacylglycerol concentration and the serum total cholesterol concentration. No clear differences between the effects of the two types of resistant starch (raw starch v. retrograded starch) were found except that raw potato starch hardly stimulated H2 excretion and led to lower amounts of propionic and butyric acids in the caecal contents than the other starches. The results suggest that dietary resistant starch reduces energy absorption leading to less abdominal depot fat and lower serum triacylglycerol concentrations.

Resistant starch decreases serum total cholesterol and triacylglycerol concentrations in rats.

Rats were meal-fed semipurified diets containing a low (0.8 g/MJ) and a high (9.6 g/MJ) amount of resistant starch (RS) or various amounts of RS (0.8 to 9.6 g/MJ) and guar gum (0 to 8.8 g/MJ). In one experiment, rats were fed the low and high RS diets in three dietary regimens (ad libitum consuming, 12 h ad libitum/12 h food deprived, and meal fed). Effects of RS and guar gum on serum postprandial and postabsorptive concentrations of total cholesterol (TC) and triacylglycerol (TAG), growth, hydrogen excretion, tissue weights and contents of small intestine and cecum, and pH of cecal contents were investigated. In addition, effects of RS on food intake, de novo hepatic synthesis of fatty acids and neutral sterols, and on lipoprotein lipase activity and weight of epididymal fat pads were investigated. Compared with feeding the low RS diet, the high RS diet reduced the serum TC and TAG concentrations, with these effects observed after 1 and 2 wk of feeding, respectively. The dietary regimen did not influence the effect of RS on the serum TC and TAG concentrations, but it did affect the serum TAG concentration. Resistant starch had no effect on the hepatic synthesis of fatty acids and neutral sterols or on the lipoprotein lipase activity in epididymal fat pads. Guar gum also reduced the serum TC concentration, but it had no effect on serum TAG concentration. The tissue weights and contents of small intestine and cecum as well as hydrogen excretion increased with increasing amounts of dietary RS and guar gum, whereas the pH of cecal contents decreased. No effects of RS on food intake and total body weight gain were found, whereas guar gum decreased weight gain. Feeding the high RS diet also led to a lower weight of the epididymal fat pads. We conclude that dietary RS can reduce serum TC and TAG concentrations and fat accretion.

Hepatic de novo fatty acid synthesis in the rat.

Generally, the rate of hepatic de novo fatty acid (FA) synthesis (lipogenesis) in vivo is determined by measuring the amount of newly synthesized FA present in the liver 1 h or less after injection of label (3H2O) for FA synthesis (1-hour value of labelled FA). Since this value may well be affected by momentary conditions, our objective was to investigate whether the amount of labelled FA present in the liver 24 h after injection of 3H2O can be used as a parameter of lipogenesis (24-hour value of labelled FA). To this end, effects of the amounts of dietary fat, sucrose and linoleic acid and the effect of meal feeding versus d libitum feeding on this 24-hour value were investigated. The 24-hour value decreased with the dietary fat level and was higher in rats fed a diet in which starch was partly replaced by sucrose [20% of metabolizable energy (E%)]. This is in accordance with literature data on the 1-hour value of labelled FA. No effect of meal feeding versus ad libitum feeding on the 24-hour value of labelled FA was found. Furthermore, no significant effect of the dietary linoleic acid level (1-10 E%) on the 24-hour value of labelled FA was found, although when lipogenesis was stimulated by feeding a diet containing 20 E% sucrose, the 24-hour value tended to be higher at 1 E% linoleic acid than at 2.5 E% linoleic acid or higher.

Effects of type and amount of dietary fat on rabbit and rat lymphocyte proliferation in vitro.

To investigate whether dietary linoleic acid inhibits lymphocyte proliferation, rabbits were fed diets containing 35% of the digestible energy (35 en%) as sunflower seed oil (25 en% linoleic acid) or palm oil (3.5 en% linoleic acid). No differences in the mitogen-induced proliferation of peripheral blood lymphocytes (PBL) or splenocytes or in the effect of sera on PBL proliferation were observed. To investigate whether the amount of dietary fat affects lymphocyte proliferation, rats were fed diets containing 10 or 35 en% as fat. No difference in the mitogen-induced proliferation of splenocytes was obtained. However, serum from fed rats but not from fasted rats of the 35 en% fat group inhibited splenocyte proliferation, in comparison with serum from rats of the 10 en% fat group. Removing chylomicrons from the sera did not affect proliferation. The very low density lipoprotein + chylomicron fraction of the plasma inhibited proliferation. The inhibition was stronger for the 35 en% fat group than for the 10 en% fat group and was increased by fasting. No systematic differences in the effects on proliferation were obtained with the low or high density lipoprotein fractions of both groups. Diets containing a high amount of linoleic acid do not inhibit lymphocyte proliferation. The amount of dietary fat might affect lymphocyte proliferation through one or more factors in the plasma.