More Evidence That Nuts Are Good For You

Cardiovascular disease was inhibited to a greater degree by a Mediterranean diet supplemented by olive oil or nuts compared to a control low fat diet.  Abstract:

Background Observational cohort studies and a secondary prevention trial have shown inverse associations between adherence to the Mediterranean diet and cardiovascular risk. Methods In a multicenter trial in Spain, we assigned 7447 participants (55 to 80 years of age, 57% women) who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was a major cardiovascular event (myocardial infarction, stroke, or death from cardiovascular causes). After a median follow-up of 4.8 years, the trial was stopped on the basis of a prespecified interim analysis. In 2013, we reported the results for the primary end point in the Journal. We subsequently identified protocol deviations, including enrollment of household members without randomization, assignment to a study group without randomization of some participants at 1 of 11 study sites, and apparent inconsistent use of randomization tables at another site. We have withdrawn our previously published report and now report revised effect estimates based on analyses that do not rely exclusively on the assumption that all the participants were randomly assigned. Results A primary end-point event occurred in 288 participants; there were 96 events in the group assigned to a Mediterranean diet with extra-virgin olive oil (3.8%), 83 in the group assigned to a Mediterranean diet with nuts (3.4%), and 109 in the control group (4.4%). In the intention-to-treat analysis including all the participants and adjusting for baseline characteristics and propensity scores, the hazard ratio was 0.69 (95% confidence interval [CI], 0.53 to 0.91) for a Mediterranean diet with extra-virgin olive oil and 0.72 (95% CI, 0.54 to 0.95) for a Mediterranean diet with nuts, as compared with the control diet. Results were similar after the omission of 1588 participants whose study-group assignments were known or suspected to have departed from the protocol. Conclusions In this study involving persons at high cardiovascular risk, the incidence of major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet. (Funded by Instituto de Salud Carlos III, Spanish Ministry of Health, and others; Current Controlled Trials number, ISRCTN35739639 .).

Health Eating And Mortality: Confirming Common Sense

By popsique - Dieta Mediterranea, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=1380032

Hopefully, readers of this blog know by now the importance of a healthy diet - emphasizing fruits, vegetables, whole grains, and unsaturated fats. However, it is comforting to have this knowledge, this common sense, legitimized by study.  Thus, read the following abstract about reduced risk of death with healthy diet consumption over time:

BACKGROUND:

Few studies have evaluated the relationship between changes in diet quality over time and the risk of death.

METHODS:

We used Cox proportional-hazards models to calculate adjusted hazard ratios for total and cause-specific mortality among 47,994 women in the Nurses' Health Study and 25,745 men in the Health Professionals Follow-up Study from 1998 through 2010. Changes in diet quality over the preceding 12 years (1986-1998) were assessed with the use of the Alternate Healthy Eating Index-2010 score, the Alternate Mediterranean Diet score, and the Dietary Approaches to Stop Hypertension (DASH) diet score.

RESULTS:

The pooled hazard ratios for all-cause mortality among participants who had the greatest improvement in diet quality (13 to 33% improvement), as compared with those who had a relatively stable diet quality (0 to 3% improvement), in the 12-year period were the following: 0.91 (95% confidence interval [CI], 0.85 to 0.97) according to changes in the Alternate Healthy Eating Index score, 0.84 (95 CI%, 0.78 to 0.91) according to changes in the Alternate Mediterranean Diet score, and 0.89 (95% CI, 0.84 to 0.95) according to changes in the DASH score. A 20-percentile increase in diet scores (indicating an improved quality of diet) was significantly associated with a reduction in total mortality of 8 to 17% with the use of the three diet indexes and a 7 to 15% reduction in the risk of death from cardiovascular disease with the use of the Alternate Healthy Eating Index and Alternate Mediterranean Diet. Among participants who maintained a high-quality diet over a 12-year period, the risk of death from any cause was significantly lower - by 14% (95% CI, 8 to 19) when assessed with the Alternate Healthy Eating Index score, 11% (95% CI, 5 to 18) when assessed with the Alternate Mediterranean Diet score, and 9% (95% CI, 2 to 15) when assessed with the DASH score - than the risk among participants with consistently low diet scores over time.

CONCLUSIONS:

Improved diet quality over 12 years was consistently associated with a decreased risk of death. (Funded by the National Institutes of Health.).

An example of a healthy eating index can be found here.

Mediterranean Diet And Metabolic Syndrome

By popsique - Dieta Mediterranea, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=1380032

Take a look at this paper.  Key points: First, rather than concentrate on effects of specific nutrients in isolation, it is better to consider a diet as a whole, with all its components working together.  Second, conformation that the typical Western diet contributes to metabolic syndrome. Third, we again see the virtues of the Mediterranean diet.  Fourth, the benefits of that latter diet may be in large part due to "high amounts of mono- and polyunsaturated fatty acids, bioactive polyphenols and dietary fiber."   These are things hopefully we all already know, but confirmation is comforting.  And it should be clear that "high consumption of meat or meat products, snacks, baked desserts and sugar-sweetened beverages" is absolutely no good for anyone's health.  Abstract:

Metabolic syndrome (MetS) is a cluster of risk factors that significantly increases the risk of cardiovascular disease. The lack of universally accepted diagnosis criteria makes it difficult to know the real prevalence of MetS in both adult and pediatric population. Lifestyle, especially nutritional habits and physical activity, have been suggested to be independent risk factors for the development of MetS. Recent studies highlight the need to prioritize overall dietary patterns, rather than isolated nutrients, to better appraise the associations between nutritional habits and MetS. In this review we summarize recently published intervention trials and systematic reviews that evaluated the association between overall dietary patterns and the risk of MetS. Westernized dietary patterns, characterized by a high consumption of meat or meat products, snacks, baked desserts and sugar-sweetened beverages, which provide high amounts of saturated fatty acids and simple carbohydrates as added sugars, have been associated with higher risk of MetS. In contrast, more traditional dietary patterns, including the Mediterranean dietary pattern (MDP), characterized by a high consumption of vegetables, fruits, whole cereals and fish are associated with a reduced risk of MetS. The main characteristics of the MDP include a high consumption of nuts and olive oil, resulting in a relatively fat-rich pattern that provides high amounts of mono- and polyunsaturated fatty acids, bioactive polyphenols and dietary fiber. Strong evidence is accumulating to support that a closer conformity with the MDP is inversely associated with the incidence of MetS, cardiovascular risk factors, diabetes and cardiovascular disease.

Mediterranean Diet, Hunger and Cancer

Evolutionary, our ancestors were able to survive on one daily meal, but sometimes went hungry for days.  Today, however, most Americans consume three meals a day with additional snacks. The notion that many small meals a day is healthy is being popularized; however, epidemiological studies have reported that a lesser number of eating episodes is associated with a reduced risk of colon cancer and other types of cancer.  Consistent with these results, rodent studies, controlled for caloric intake, have revealed that longer intervals between meals increase resistance to cancer.

Periods of strictly vegetarian diet and fasting are incorporated in many religious traditions.  For example, throughout the year, the Eastern Orthodox calendar includes 180 days of fasting, during which vegetarian days alternate with periods of complete abstinence from food. Thus, a strict Orthodox Christian observes the following weekly fasting rules: only one vegetarian meal on Wednesdays and no food on Fridays. In addition, there are prolonged periods of fasting during the year: the three main ones being the forty days before Christmas, Lent (40-48 days) and the Assumption (15 days).   According to the rules of these fasts, any meat and meat products, eggs, dairy products, fish, oil, and wine are excluded from the diet, although fish, wine, and oil are allowed on certain days of the week.  Interspersed within the long fasting periods are days or even weeks of complete abstinence from food (e.g., the week before Easter, Holy Week).  

Interestingly, this Orthodox Christian fasting regimen has been proposed as an alternative explanation for the health benefits of the Greek Mediterranean diet. Thus, the Mediterranean diet is not only rich in fiber (grains, vegetables and fruit) and olive oil, but it is accompanied by periods of fasting that might be beneficial by slowing down tumor cell growth and preventing cancer.  

The slowing of abnormal cell growth by fasting could be mediated by the changes in metabolism. What are these changes? Fasting forces the body to switch from one source of energy (carbohydrates, such as glucose), to another – fats.  According to metabolite studies, the glucose from the blood and its storage (glycogen, which is simply a chain of many glucose molecules) is utilized within the first 12 hours of complete fast. On day 2 of the fast, the body already relies on processing of fats (from the adipose tissues) to ketones as a source of energy. Does this major shift in metabolism explain the protective effect of fasting against cancer? Likely, yes. It has been long known that some cancer cells are addicted to sugar (glucose) as a source of energy; now we know that many human cancers exhibit this behavior.  

Such abnormal cells have an excess of glucose receptors on their surface, and therefore, “devour” more glucose from the blood than normal cells. Additional mechanisms also force cancer cells to rely mostly on glucose as their source of energy. Because of this dependence on glucose, the depletion of glucose (as in fasting) can result in the death of the tumor cells. Furthermore, in all cancer cells the depletion of glucose is likely to suppress all signaling pathways that support survival.

In 1921, Dr. Wilder proposed that the effects of fasting on the body could be mimicked by a diet, in which fat was the main component, the ketogenic diet. This diet consists mostly of fat; thus, the ratio of fat : protein : carbohydrate in this diet is close to 90 : 8 : 2. With this diet, the organism uses fat as its main source of energy and forms ketones the same way these compounds are produced during fasting. However, whereas in fasting the body uses its own fat storage to cope with the lack of other energy sources, during the ketogenic diet, exogenous (external) fat from the food is being processed. This difference between fasting and ketogenic diet results in very different levels of LDL cholesterol: fasting individuals compared to controls present with 12.5% lower end-total cholesterol (p < 0.001) and 15.9% lower end-LDL cholesterol (p< 0.001). Therefore, be aware that during ketogenic diet the levels of cholesterol skyrocket, and this is obviously not good for the long-term health outcomes.

Despite the ability of the fasting regimen and ketogenic diet to suppress tumor growth, the cancer therapeutic application of these approaches is limited in the U.S. These modalities are mostly applied as adjuvant (complimentary) modalities to mainstream cancer treatments. One reason to shy away from these approaches is that our medical doctors are not taught about them, and therefore, nor aware of them.

Here I did not discuss the benefits of fasting in reducing obesity and the obesity-related metabolic syndrome with its downstream consequences (e.g., cardiovascular diseases, type 2 diabetes, etc.). I also neglected to discuss the additional benefits of Mediterranean diet to human health. Hopefully, these will be subjects of future posts.

Actionables

It has been proposed that limiting the food and drink intake to 6-10 hours a day may have the same benefits as any longer-term fasting regimen. In practice, this means that one could fast  from early dinner till late breakfast next day, or skip breakfast or dinner. 

PS:
A later post also explores this topic.