Israeli Paradox: High Omega -6 Diet Promotes Disease

Also see:
Unsaturated Fats, Oxidative Stress, and Atherosclerosis
Unsaturated Fats and Heart Damage
Maternal PUFA Intake Increases Breast Cancer Risk in Female Offspring
PUFA Promote Cancer
Toxicity of Stored PUFA
Dietary PUFA Reflected in Human Subcutaneous Fat Tissue
Arachidonic Acid’s Role in Stress and Shock
Omega 6 Content of Common Foods by Matt Stone

Isr J Med Sci. 1996 Nov;32(11):1134-43.
Diet and disease–the Israeli paradox: possible dangers of a high omega-6 polyunsaturated fatty acid diet.
Yam D, Eliraz A, Berry EM.
Israel has one of the highest dietary polyunsaturated/saturated fat ratios in the world; the consumption of omega-6 polyunsaturated fatty acids (PUFA) is about 8% higher than in the USA, and 10-12% higher than in most European countries. In fact, Israeli Jews may be regarded as a population-based dietary experiment of the effect of a high omega-6 PUFA diet, a diet that until recently was widely recommended. Despite such national habits, there is paradoxically a high prevalence of cardiovascular diseases, hypertension, non-insulin-dependent diabetes mellitus and obesity-all diseases that are associated with hyperinsulinemia (HI) and insulin resistance (IR), and grouped together as the insulin resistance syndrome or syndrome X. There is also an increased cancer incidence and mortality rate, especially in women, compared with western countries. Studies suggest that high omega-6 linoleic acid consumption might aggravate HI and IR, in addition to being a substrate for lipid peroxidation and free radical formation. Thus, rather than being beneficial, high omega-6 PUFA diets may have some long-term side effects, within the cluster of hyperinsulinemia, atherosclerosis and tumorigenesis.

Cancer Lett. 1997 Jan 1;111(1-2):179-85.
Subcutaneous, omentum and tumor fatty acid composition, and serum insulin status in patients with benign or cancerous ovarian or endometrial tumors. Do tumors preferentially utilize polyunsaturated fatty acids?
Yam D, Ben-Hur H, Dgani R, Fink A, Shani A, Berry EM.
The relationships between the fatty acid composition of cancerous endometrium and ovary, and peripheral adipose tissues were studied in Israeli Jewish women, and are presented together since no differences were shown between them. The results suggest a mobilization of linoleic acid from subcutaneous and omental depots and its incorporation into tumors accompanied by a high degree of desaturation. High blood insulin concentrations characterized patients with stage I and II disease, and low concentrations characterized patients with advanced degrees of malignancy.

Am J Gastroenterol. 2011 Apr;106(4):563-73. doi: 10.1038/ajg.2011.44.
Dietary intake and risk of developing inflammatory bowel disease: a systematic review of the literature.
Hou JK, Abraham B, El-Serag H.
The incidence of inflammatory bowel disease (IBD) is increasing. Dietary factors such as the spread of the “Western” diet, high in fat and protein but low in fruits and vegetables, may be associated with the increase. Although many studies have evaluated the association between diet and IBD risk, there has been no systematic review.
We performed a systematic review using guideline-recommended methodology to evaluate the association between pre-illness intake of nutrients (fats, carbohydrates, protein) and food groups (fruits, vegetables, meats) and the risk of subsequent IBD diagnosis. Eligible studies were identified via structured keyword searches in PubMed and Google Scholar and manual searches.
Nineteen studies were included, encompassing 2,609 IBD patients (1,269 Crohn’s disease (CD) and 1,340 ulcerative colitis (UC) patients) and over 4,000 controls. Studies reported a positive association between high intake of saturated fats, monounsaturated fatty acids, total polyunsaturated fatty acids (PUFAs), total omega-3 fatty acids, omega-6 fatty acids, mono- and disaccharides, and meat and increased subsequent CD risk. Studies reported a negative association between dietary fiber and fruits and subsequent CD risk. High intakes of total fats, total PUFAs, omega-6 fatty acids, and meat were associated with an increased risk of UC. High vegetable intake was associated with a decreased risk of UC.
High dietary intakes of total fats, PUFAs, omega-6 fatty acids, and meat were associated with an increased risk of CD and UC. High fiber and fruit intakes were associated with decreased CD risk, and high vegetable intake was associated with decreased UC risk.

Pharmacology. 2016 Jun 2;98(3-4):134-170. [Epub ahead of print]
Medicines and Vegetable Oils as Hidden Causes of Cardiovascular Disease and Diabetes.
Okuyama H1, Langsjoen PH, Ohara N, Hashimoto Y, Hamazaki T, Yoshida S, Kobayashi T, Langsjoen AM.
Positive associations have been observed between cardiovascular disease (CVD) and type 2 diabetes mellitus (DM), but their causal relationship has not been clarified. Nevertheless, guidelines from relevant medical societies recommend using cholesterol lowering medication (statin) for both types of patients. Medicines with several different action mechanisms have been developed, and the effectiveness of different lifestyle modifications has been studied extensively for the prevention of DM, which was successful in improving clinical marker status in relatively short-term treatments, but none have been shown to be effective in improving long-term outcomes (mortality from CVD and all causes).
Statin-induced suppression of prenyl intermediates in the cholesterol biosynthetic pathway has been linked to stimulated atherosclerosis and heart failure. On the other hand, certain types of vegetable oil and hydrogenated oil shortened the survival of stroke-prone spontaneously hypertensive rats by decreasing platelet number, increasing hemorrhagic tendency and damaging kidney functions, which could not be accounted for by their fatty acid and phytosterol compositions. These vegetable oils and medicines such as statin and warfarin share, in part, a common mechanism to inhibit vitamin K2-dependent processes, which was interpreted to lead to increased onset of CVD, DM, chronic kidney disease, bone fracture and even mental disorder. Impaired vitamin K2-dependent processes by some types of vegetable oils and medicines, but not plasma high low density lipoprotein cholesterol, were proposed as the cause of CVD, DM and other lifestyle-related diseases. High n-6/n-3 fatty acid ratio of ingested foods, but not animal fats, was emphasized to be another risk factor for many of the diseases described above.
To date, no randomized controlled trials (RCTs) have been performed to prove the above interpretation. However, the opposite types of RCT trials have been performed by increasing the intake of high-linoleic vegetable oils and reducing that of animal fats, which resulted in increased CVD and all-cause mortality. The amounts of these vegetable oils to exhibit adverse effects in animal studies are not huge (<6 energy %), which should not be overlooked nor disregarded.

J Nutr Biochem. 2016 Nov 4;40:122-131. doi: 10.1016/j.jnutbio.2016.10.016. [Epub ahead of print]
Linoleic acid causes greater weight gain than saturated fat without hypothalamic inflammation in the male mouse.
Mamounis KJ, Yasrebi A, Roepke TA
A significant change in the Western diet, concurrent with the obesity epidemic, was a substitution of saturated fatty acids with polyunsaturated, specifically linoleic acid (LA). Despite increasing investigation on type as well as amount of fat, it is unclear which fatty acids are most obesogenic. The objective of this study was to determine the obesogenic potency of LA vs. saturated fatty acids and the involvement of hypothalamic inflammation. Forty-eight mice were divided into four groups: low-fat or three high-fat diets (HFDs, 45% kcals from fat) with LA comprising 1%, 15% and 22.5% of kilocalories, the balance being saturated fatty acids. Over 12 weeks, bodyweight, body composition, food intake, calorimetry, and glycemia assays were performed. Arcuate nucleus and blood were collected for mRNA and protein analysis. All HFD-fed mice were heavier and less glucose tolerant than control. The diet with 22.5% LA caused greater bodyweight gain, decreased activity, and insulin resistance compared to control and 1% LA. All HFDs elevated leptin and decreased ghrelin in plasma. Neuropeptides gene expression was higher in 22.5% HFD. The inflammatory gene Ikk was suppressed in 1% and 22.5% LA. No consistent pattern of inflammatory gene expression was observed, with suppression and augmentation of genes by one or all of the HFDs relative to control. These data indicate that, in male mice, LA induces obesity and insulin resistance and reduces activity more than saturated fat, supporting the hypothesis that increased LA intake may be a contributor to the obesity epidemic.

International Science and Investigation journal, [S.l.], v. 5, n. 5, p. 157-168, Nov. 2016
Vegetable Oils Consumption as One of the Leading Cause of Cancer and Heart Disease.
This review takes a deep look at increases in the incidence of cancer and heart disease after the introduction of industrial vegetable oils in the world. Most vegetable oils are highly processed and refined products, which completely lack the essential nutrients. Omega-6 Linoleic acid from vegetable oils increases oxidative stress in the body of humans, contributing to endothelial dysfunction and heart disease. The consumption of these harmful oils which are high in mega-6 polyunsaturated fats results in changing the structure of cell membrane which contribute to increasing inflammation and the incidence of cancer.

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