The Mediterranean Diet

By Truman Madden

Section 1: What is the Mediterranean Diet?

Section 2: Sample Diet Plan

Section 3: What Do the Studies Show?

Section 4: References


Section 1: What is the Mediterranean Diet?

The Mediterranean diet is a lifestyle, rather than a “diet”. The intention of the plan is to continue the eating habits long term with the goal of reducing the risk of various ailments, specifically of the cardiovascular system. The macronutrient profile is sided with fats and proteins, though carbohydrates are included. The key to the carbohydrates is that they are derived from whole grains, fruits, and the small amounts found in various vegetables. The fats and protein in the diet are obtained from nuts, legumes, seafood, lean poultry, and olive oil. By following this plan, a person is more likely to abstain from various foods with properties that have been charged with blame to induce problems in the modern human. These foods include red meats, processed sugary “foods”, and saturated fats (butters, fatty meats, cheese, etc.).

The inspiration for this diet, as the name implies, derives from the cuisine of the people who live near the Mediterranean Sea. Their rich culture has cultivated a culinary style based on socializing and whole foods exploding with nutrients. Many recent research projects have shown this diet to help with heart health by reducing the amount of LDL cholesterol, reducing risks of fatal cardiac episodes, lowering cancer risk, and helping with reducing the risk of Parkinson’s and Alzheimer’s disease (Assy, et al., 2009) (Barak & Fridman, 2017) (Petersson & Philippou, 2016). There are even some studies associating the diet with a helpful effect for blood sugar regulation in the prevention of type 2 diabetes (Esposito, et al., 2017). Lastly, the diet allows the consumer to ingest foods rich in various micronutrients that have largely been lost in the creation of processed foods. It is important to note that all these great findings are based on epidemiological studies that do have various flaws and limitations. Everyone is different and reacts differently to various diets. Care should be taken to optimize your own diet plan to suit your caloric needs and lifestyle.


Section 2: Sample Diet Plan

(intended for active people – total calories 2,135)

Breakfast:

¾ cup whole grain oatmeal, ½ cup blueberry, ⅕ tbsp walnuts, 2 tsp honey; 444 calories

Mid-Morning Snack:

½ cup whole almonds; 411 calories

Lunch:

2 cups mixed greens, 1/2 cup cucumber slices, 8 cherry tomatoes halved, 2 Tbsp. feta cheese, 8 Kalamata olives pitted, ½ tbsp olive oil and balsamic vinegar, ½ whole grain pita bread, 4 oz chicken breast; 550 calories

Mid-Afternoon Snack:

2 tbsp almond butter, 1 medium apple; 300 calories

Dinner:

6 oz. cod fillet cooked in olive oil, vegetable medley 2 cups, 1 avocado; 400 calories

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Section 3: What Do the Studies Show?

In this vast world of corporate driven promotions of various ways to live your life, you may be still wondering which diet is going to keep you from dying from morbidities that were in theory preventable through diet. What are these preventable morbidities you might ask? Some common causes of diet related death include stroke, myocardial infarction, type 2 diabetes, obesity, kidney failure,  and liver failure. Conditions that many Americans do not choose to address until an extreme condition arises. Classical research investigating ways to prevent diet related death, have looked at various aspects of health such as blood pressure, resting heart rate, weight, HDL/LDL, etc. The identification of biomarkers has expanded recently due to our increased understanding of biochemistry and the use of of better technology to dive deeper into the regulation physiological activities down to the inner workings of liver hepatocytes.

Keeping deep science dialect at bay, let’s address the original question: is there a diet that is truly superior to others when seeking a longer life? The answer is a sturdy maybe. The sturdy maybe lies within the dietary consumption pattern called the “Mediterranean diet”. Without much thought, a person could likely think of the potential food options available just based on the name! Whole grain pastas, fish straight from the market, the finest oils from the local olive fields, fresh veggies grown in mi mama’s crop located just past the goat pasture, and red wine from papa Degario’s personal cellar. What a life this would be to emulate in land far beyond the sapphire waters of the Mediterranean. As it turns out, many health advocates are encouraging people to take up this wholesome food routine in the hopes of decreasing the likelihood of developing one of the aforementioned morbidities (Bach-Faig, et al., 2011).

The evidence for the effectiveness of the Mediterranean diet is, like most research, debatable in its universal applicability (Lilienfeld, 1983). Numerous variables pertaining to study cohort age, genetics, gender, substance use history, environmental pollution, and current weight-related risk factors could be used to make the studies seem more revelational. With all that being said, you still want answers; what has been learned about the Mediterranean diet and its’ ability to reverse years of internal abuse through binge drinking, smoking phases in adolescence, and eating whole pizzas at midnight out of spite for the disappointments of life?

In no particular order, the first desirable effect of the Mediterranean diet is lowering the risk of type 2 diabetes. In a nutshell, the modern epidemic of type 2 diabetes is spurned by the excessive intake of sugar and simple carbohydrates (Bach-Faig, et al., 2011). When the excessive consumption of the sugars and carbohydrates are combined with a sedentary lifestyle, risk for accumulation of fat stores around vital organs increases. This fat deposition during a sedentary lifestyle is due to the tendency of unutilized sugar in the blood to be converted to fats and stored in adipose tissue. Hence, the common advice to avoid simple carbohydrates and sugars around bedtime since the body will be in a lower physical activity state, leading to the consumed nutrients being converted to fat (Stanhope, 2015). Along with being in a lowered metabolic state, increased insulin levels are also associated with weight gain in type 2 diabetics (Brown, et al., 2017). The proposed mechanism of this increased insulin induced weight gain goes as follows:

  1. A person habitually consumes too many carbohydrates and sugars
  2. The glucose produced by these foods are shuttled into glycogen stores using insulin
  3. Over the years, too much insulin production to utilize the excess glucose consumption leads to resistance; similarly to how how drug addicts needs higher doses to achieve the same high until eventually the drugs don’t work anymore to activate the neurotransmitter release because the receptors for the neurotransmitters are overused until they no longer function
  4. When the pancreas is insulin resistant, those less insulin is released
  5. The decrease in insulin means that there are glucose molecules in the blood
  6. Unutilized glucose in the blood turns into fat accumulation in the body.

    Given this proposed mechanism, once must ask themselves, “how can I prevent this terrible internal environment from happening to me?”. The answer is to consume a diet which decreases the amount of sugars and carbohydrates, i.e. the Mediterranean diet. In fact, adherence to the Mediterranean diet has been shown to reduce incidence of type 2 diabetes by 23% (Esposito, et al., 2017). Two important biomarkers to predict new cases of type 2 diabetes in people are interleukins and C reactive proteins. Interleukins and C reactive proteins are released by the immune system in response to a stressor on the body. The result of this release is inflammation. People who have type 2 diabetes or are pre-diabetic have greater amounts of inflammation due to the stress placed upon the pancreas due to insulin resistance. This inflammation can in turn be reduced by following a Mediterranean diet (Esposito, et al., 2017, Greco, et al., 2014). The cause of the reduced inflammation is that the basal insulin levels are also lowered (Esposito, et al., 2017, Zelber-Sagi, et al., 2017). Thus, the positive effect on the pancreas via the Mediterranean diet is displayed.

Even people who are currently type 2 diabetics greatly benefit from making the switch over to the eating pattern, with some studies show remission of the disease in 34-74% of the test subjects (Esposito, et al., 2017). The great variations seen in the different studies can be partly explained by the difficulty in controlling subject’s adherence to the diet. The participants are also all in different stages of their diabetes with different genetic induced physiological patterns. Thus, we see the great bane of epidemiological research! Variances that cannot easily be controlled occur, creating different variability in statistical significance from study to study. Even with the variance, it is is a positive life-style change that one can use to help reduce the risk of developing type 2 diabetes.

Earlier in the type 2 diabetes discussion, we talked about how fat accumulates in the body due to excess glucose in the blood. When fat accumulation gets out of hand it can also lead to obesity. Obesity is defined as having a Body Mass Index(BMI) over 30 (Greco, et al., 2014). These calculations are most useful for people who are not physically active. (For body builders, the BMI may be skewed when larger amounts of muscle mass are present.)  Being in the obese category predisposes a person to acquiring cardiovascular disease, type 2 diabetes (duh), metabolic syndrome, nonalcoholic fatty liver disease, and cancer (Greco, et al., 2014). With these kinds of risk factors on the line, there is a glaring incentive to find a maintainable solution to the problem beyond surgical procedures and pharmaceuticals.

The Mediterranean Diet is one of the proposed solutions, with studies showing just how promising the eating plan can be when done properly. One study showed that obese subjects who were instructed to follow a Mediterranean diet lost on average 4 kg in 4 months. Though this number does not sound like much, the evidence is there that the diet alone can induce weight loss. Keep in mind that these subjects were not following a physical activity regime when on the diet plan. The results could be predictively higher had they been on one as physical activity across the boards is shown to improve results of various diet plans (Greco, et al., 2014).

Another notable biomarker decrease seen in obese subjects following their participation in the Mediterranean diet was levels of circulating leptin. Leptin is a hormone released by fat cells to regulate appetite. As a person eats, the leptin is slowly released and interacts with receptors in the hypothalamus. When the fat cells increase greatly, so does leptin secretion. This increased release leads to desensitization of the receptors in the hypothalamus. Thus, achieving a state of satiety becomes difficult despite having high amount of energy stores available. The ensuing behavior is likely consumption of more energy dense foods which are converted to glucose. This increases blood glucose levels, leading to further increases in fat production. Following one month participation on the Mediterranean diet, the average blood levels of leptin decreased from 47 ng/mL to 35 ng/mL (Greco, et al., 2014). By decreasing the amount of leptin circulating in the body, the Mediterranean diet has the potential to decrease inappropriate feelings of hunger in people who are struggling with obesity.

It is important to note that the results of a diet and exercise program in obese people can be varied due to genetics. One example of a gene that affects overall subject outcomes is the rs266729 adiponectin gene (Antonio de Luis, et al., 2018). The adiponectin protein functions in the body to increase fatty acid oxidation and breakdown, leading ultimately to weight loss. In other words, it increases the body’s ability to burn fat stores. If a person has a defect in the gene coding for the adiponectin protein, they may not be burning fat stores efficiently for energy production, even when placed on an effective diet and exercise program (Antonio de Luis, et al., 2018).

The good news is that when a person does have a functional adiponectin gene, the Mediterranean diet paired with a exercise regime can effectively increase adiponectin production (Antonio de Luis, et al., 2018). After 3 months of regular aerobic activity and a hypocaloric Mediterranean diet, obese patients saw their adiponectin levels go from an average of 28.7 ng/dL to 39.1 ng/dL. This increase corresponds to an increase in the amount of fat burning within diet participants (Antonio de Luis, et al., 2018). The same cohort also saw their average leptin levels decrease from 92.3 ng/dL to 75.1 ng/dL, further helping with their progress towards a healthier lifestyle. Even the people who had a defect in their rs266729 adiponectin gene saw decreases in their serum leptin concentration (Antonio de Luis, et al., 2018).

What about cardiovascular disease and events such as stroke or myocardial infarction that can cause devastating effects in a matter of minutes?  Before diving into the research about the effects of the Mediterranean diet, lets define both. A stroke is when there is a blockage or rupture of a vessel which delivers oxygenated blood to the brain (CDC). A myocardial infarction is when a portion of the heart muscle does not receive adequate blood flow for a duration of time (CDC). How does a person decrease their risk of experiencing a stroke or myocardial infarction? Data shows that consuming a diet high in sweets, processed meats, salt, red meat, and trans fat increases the instances of a stroke and myocardial infarction (Zelber-Sagi, et al., 2017). For example:

  1. High salt in the diet leads to blood containing more solutes, which in turn raises blood pressure (Ha, S. K., 2014).  
  2. Red meat contains fats which will become low density lipoproteins (LDL). These LDLs will in turn stick to the walls of blood vessels carrying oxygenated blood (Assy, et al., 2009).
  3. Sugars found in various sweets within the standard American diet causes multiple blood pressure raising pathways to be activated, along with placing pesky free floating glucose into the blood supply which will lead to adipose tissue production if unutilized (He, et al., 2015)
  4. Heavily processed foods containing trans fats are not properly digested by the body and in turns creates unhealthy bi products which are difficult to excrete; placing strain on the cardiovascular system  (Zelber-Sagi, et al., 2017).

The Mediterranean diet omits the aforementioned foods that increase the likelihood of a stroke and myocardial infarction. The high volume of olive oil intake in the Mediterranean diet decreases the amount of oxidized LDL(bad fat) without decreasing HDL(good fat) (Assy, et al., 2009). While the LDL tends to stick to the blood vessel walls, the HDL is capable of carrying away build-up within the vessels (Hernaez, et al., 2017). The problem in both strokes and myocardial infarctions is that there are obstructive masses in the blood vessels preventing the delivery of oxygenated blood to the heart and brain. If a person consumes a Mediterranean diet which will decrease blood pressure and reduce the amount of plaque in the blood vessels; there will promote cardiovascular and cerebrovascular health (Hernaez, et al., 2017). One study found a 44% reduction in the occurrence of cardiac events in those who had not had cardiac instance previously and a 24% reduction in those who had a previous cardiac event (Assy, et al., 2009). This data shows just how powerful the diet can be in preventing strokes and myocardial infarctions, even if a person already has cardiac problems.

As mentioned before, a diet high in simple carbohydrates paired with a sedentary lifestyle leads to fat accumulation around vital organs. Fat tissue around the liver is really bad news as it can cause non alcoholic fatty liver disease (Zelber-Sagi, et al., 2017). To demonstrate just how important it is to have a healthy liver, lets review the vital functions of the liver (Wikipedia):

  1. Storage site for glycogen
  2. Detoxification of various toxins consumed via food, drinks, and drugs
  3. Monitors blood glucose levels
  4. Bile secretion; bile helps with the digestion of dietary fats
  5. Gluconeogenesis; the process of turning proteins into energy

Ineffective detoxification by the liver prolongs the negative neurotoxic effects activities such as binge drinking, overeating, and recreational drug use have on the affected regions of the body (Zeremski & Martinez, 2017). Though the medical community does not condone those behaviors, people will partake due to a number of reasons. Choosing to not be reckless AND having a healthy diet is the preferred option. The Mediterranean diet can decrease the amount of fat mass accumulation around the liver, improving the function (Zelber-Sagi, et al., 2017). It does so by being rich in healthy fats and complex carbohydrates that are digested at a pace to which the pancreas is able to keep up in pace of glucose release into the blood (Zelber-Sagi, et al., 2017)(Esposito, et al., 2017).

Not only does a well tuned glucose-insulin relationship help the liver, but also the mechanism of digestion of Monounsaturated fatty acids (MUFA) found in olive oil aids with keeping the liver fat deposition low (Assy, et al., 2009). The data shows that consumption of MUFA in olive oil increased the amount of triglyceride release from the liver while decreasing the amount of fatty acids that flow back to the liver from other adipose tissue (Assy, et al., 2009). This triglyceride release from the liver displays that the olive oil is contains a substance of sorts which leads to the metabolic breakdown of the liver adipose tissue. The exact mechanism is unknown at this time. However, the data is promising going forward to prevent and treat fatty liver disease.

Lastly, what is known about the Mediterranean diet’s effect on cancer growth and prevention? Well, there is some positive data in a 50% reduction of oropharyngeal, esophageal and laryngeal cancer risks in people who smoke or have been smokers (Barak & Fridman, 2017). This is promising to those who are in the cycle of quitting or who have already quit with their worries about longevity and being able to sustain a life long enough to enjoy their loved ones even though they made poor health decisions in the past. Ordinary non smoking people who adhered to a Mediterranean diet have had conflicting significant data about their risk of developing cancer. The overall cancer occurrence factor is positive in that analysis of research shows that people adhering to the diet in general have a slightly lower incidence of a cancer (Dinu, et al., 2017). The data is a bit weak as the volume of studies and the cohort size in the existing studies are low. Once again, the significance of epidemiological studies can be less than desired in terms of delivering answers.

If you are still reading this blog at this point, congratulations. You made it through the information that people despise visiting the doctor to hear. Who wants to be lectured about their blood pressure, heart rate, HDL/LDL, etc.? If you truly despise health lectures from rich people in white coats, the best option is learn the information for yourself and take care of your body using methods supported by research. Oh wait, it looks like you have already learned a way to take care of yourself by reading the preceding pages. The pages that were supported by research….. Thus, you should look into making some changes in your dietary pattern so that you too can reap the benefits of the Mediterranean diet! At the very least, eliminate sugary garbage from your diet, exercise 3 times a week for at least 30 minutes each session, reduce red meat intake, and maybe even give those weird hippies at the farmer’s market a chance.

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Section 4: References

Antonio de Luis, D., Primo, D., Izaola, O., Gomez-Hoyos, E., Gomez, J.J.L., Ortola, A., Aller, R. (2019). Role of the variant in adiponectin gene rs266729 on weight loss and cardiovascular risk factors after a hypocaloric diet with the Mediterranean pattern. Nutrition, 60:1-5

Assy, N., Nassar, F., Nasser, G., & Grosovski, M. (2009). Olive oil consumption and non-alcoholic fatty liver disease. World journal of gastroenterology, 15(15), 1809-15.

Bach-Faig, A., Berry, E., Lairon, D., Reguant, J., Trichopoulou, A., Dernini, S., Serra-Majem, L. (2011). Mediterranean diet pyramid today. Science and cultural updates. Public Health Nutrition, 14(12A), 2274-2284. doi:10.1017/S1368980011002515

Barak, Y., & Fridman, D. (2017). Impact of Mediterranean Diet on Cancer: Focused Literature Review. Cancer genomics & proteomics, 14(6), 403-408.

Brown, A., Guess, N., Dornhorst, A., Taheri, S., Frost, G., (2017). Insulin‐associated weight gain in obese type 2 diabetes mellitus patients: What can be done? Diabetes Obes Metab. 19:1655–1668. https://doi.org/10.1111/dom.13009

Center for Disease Control (CDC), https://www.cdc.gov/stroke/about.htm , https://www.cdc.gov/heartdisease/heart_attack.htm

Dinu, M., Pagliai, G., Casini, A.  Sofi, F. (2017). Mediterranean diet and multiple health outcomes: an umbrella review of meta-analyses of observational studies and randomised trials. European Journal of Clinical Nutrition.

Esposito, K., Maiorino, M.I., Bellastella, G., Panagiotakos, D.K, Guigliano, D., (2017). Mediterranean diet for type 2 diabetes: cardiometabolic benefits. Endocrine, 56:27. https://doi.org/10.1007/s12020-016-1018-2

Greco, M., Chiefari, E., Montalcini, T., Accattato, F., Costanzo, F. S., Pujia, A., Foti, D., Brunetti, A., Gulletta, E., (2014). Early effects of a hypocaloric, Mediterranean diet on laboratory parameters in obese individuals. Mediators of inflammation.

Ha S. K. (2014). Dietary salt intake and hypertension. Electrolyte & blood pressure, 12(1), 7-18.

He, F.J. & MacGregor, G.A., (2015). Salt and sugar: their effects of blood pressure. European Journal of Physiology, 467:577. https://doi.org/10.1007/s00424-014-1677-x

Hernáez, Á., Castañer, O., Elosua, R., Pinto, X., Estruch, R., Salas-Salvadó, J., Corella, D., Borau, F., Serra-Majem, L., Fiol, M., Ortega-Calvo, M., Ros, E., Martínez-González, M., de la Torre, R., Carmen López-Sabater, M., Fitó, M., (2017). Mediterranean Diet Improves High-Density Lipoprotein Function in High-Cardiovascular-Risk Individuals. Clinical Perspective: A Randomized Controlled Trial. Circulation, 135. 633-643.

Lilienfeld A. M. (1983). Practical limitations of epidemiologic methods. Environmental health perspectives, 52, 3-8.

Stanhope K. L. (2015). Sugar consumption, metabolic disease and obesity: The state of the controversy. Critical reviews in clinical laboratory sciences, 53(1), 52-67.

Zelber‐Sagi S, Salomone F, Mlynarsky L. (2017) The Mediterranean dietary pattern as the diet of choice for non‐alcoholic fatty liver disease: Evidence and plausible mechanisms. Liver International, 37:936–949. https://doi.org/10.1111/liv.13435

Zeremski, M. and Martinez, A. (2017), Liver Disease and Fibrosis Assessment in Substance Use–Related Disorders. Clinical Pharmacology in Drug Development, 6:164-168. doi:10.1002/cpdd.312

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