Connection Between Diet and Chronic Diseases

Scientists have been trying for decades to establish a connection between the consumption of food and its effect on the health of the person. Several studies have given extraordinary results. For, e.g., use of whole grains has been associated with lowering of disease risk, but when similar items are consumed with meat, health affects adversely, whereas fruits and vegetables potentiate the efficacy of whole grain. So, the question arises whether the connection of single nutrient with health should be studied? Or what if the best way is to establish the context of the whole diet with the existence of chronic diseases?

Moreover, there are several factors which affect the choice of a person to adopt a particular diet. Such factors include the availability of food, weather conditions, purchasing power, advertisements, and publications of government guidelines on dietary intake. In this article, we will study the components of diet recommended by nutrition communities and their efficacy in the improvement of health conditions. Along with this, we will go through a couple of studies which establish a secure connection between diet and occurrence of chronic diseases particularly hypertension, type 2 diabetes, cardiovascular diseases, dental disorders, obesity, osteoporosis, and cancer.

The report of the Joint WHO/FAO Expert Consultation which took place in Geneva from 28 January to 1 February 2002 recommended several changes in the diet given by WHO Study Group in 1989. The below table highlights the major dietary elements which were reported a significant difference in their intake values:

Diet in terms of quality and quantity plays a significant role in the management of diabetes. A high intake of calories daily increases the risk of the disease. While keeping BMI and another chance separate, quality of carbohydrates and fats consumption also causes the effects on the condition.^[3] E.g., high dietary glycemic load (GL) and trans fatty acids escalate the state of diabetes, whereas daily intake of cereal fiber and polyunsaturated fats are meant to decrease the risk associated with the disease. As per studies increasing the daily servings of whole-grain intake by two will drop 21% of risk attached with diabetes.^[3]

Research has revealed the increased threat on the excessive intake of sugar-sweetened beverages (SSB). The factors which contribute to the worsening of cardiometabolism are the increased weight gain, enhanced insulin demand, dyslipidemia, and chronic inflammation. The components of SSB, i.e., rapidly absorbing carbohydrates, mainly sucrose, are responsible for an increase in the dietary GL, which ultimately escalate the glucose levels in the blood. The responsive increased demand for insulin will lead to the risk of destruction of beta cells of the pancreas in the long run.

The dietary patterns vary from areas to areas which describe the different rate of diseases in the various nations. In developing countries of Asia, the population is adapting to the industrialized and urban food environment. Along with this, their sedentary lifestyle being the cause of central adiposity majorly impact the spread and severity of diabetes.

In-Depth research is going on to study the impact of dietary protein on the renal condition of the patients. One such study was published where the efficacy of restricting dietary protein on the diabetic and nondiabetic bad renal health patients was studied. A total of 5 reviews were conducted, which included 1413 nondiabetic and 108 types one diabetic renal disease patients, respectively. Specific study models were created to determine the risk of progression of the disease by dividing the individual group of patients further into two parts. One was kept on low diet protein, whereas another was given a standard protein diet. The observation of studies was as follows:

• In nondiabetic renal disease patients maintained on a low protein diet, a significant risk of renal failure and death was reduced.
• In insulin-dependent renal disease patients kept on a low protein diet, a significant decrease in urinary albumin level, a decline in glomerulation filtration rate or creatinine clearance were observed.
• No significant difference in the reduction of risk between diabetic and nondiabetic patients could be observed.

Therefore, the study concluded that the restriction of dietary protein considerably slowed the progression of renal disease in both diabetic and nondiabetic patients.

What Are Whole Grains?

Wheat as one third, rice as one-fourth of the total grain production and corn are considered as significant cereal grains. Oats, barley, triticale, sorghum, and millet are included in the minor grains. Consumption of grains requires predefined treatments such as milling, heat extraction, cooking, parboiling, and various other processing. Grains are rich in content of dietary fiber, little in fat, concentrated sources of starch, approx. 10-15% protein content, high sources of Vitamin B, and trace minerals.

Dietary recommendations by the regulatory bodies say for the consumption of whole grains to prevent cancers primarily gastrointestinal such as gastric and colonic cancers. A diverse list of components of entire grain items justifies their protective mechanisms. The principal mechanism includes the compounds which affect the gut environment such as dietary fiber, resistant starch, indigestible compounds. Other than this, compounds that function as antioxidants such as trace minerals and phenolic compounds and compounds with potential hormonal effects such as phytoestrogens also play a significant role in the efficacy of whole grains. Seeing an extensive list of nutrients, the protective mechanisms of whole grains has been divided broadly into four categories:

• The large intestinal model
• The antioxidant model
• The lignan and phytoestrogen model
• Other potential mechanisms

Large Intestinal Model

This model specifies the protective mechanism of dietary fiber, indigestible carbohydrates, and resistant starch. Indigestible carbohydrates when reaches the colon, get fermented by intestinal microflora and production of short-chain fatty acids takes place. Production of short-chain fatty acids has been meant to decrease the serum cholesterol level and thereby reduce the risk of cancer. Stephen^[5] explained the difference in the actions of the different grains on behalf of their properties such as chemical composition, solubility, physical form, presence of lignin, phyate, protein, and minerals. The dietary fiber can be divided further into two parts: soluble and insoluble fiber. Soluble fiber results in cholesterol-lowering and improved glucose levels, whereas insoluble fiber work as a laxative. Rice doesn’t contain any significant soluble fiber, and after that wheat is lowest in the content of soluble fiber. Oats, rye, and barley contain approximately one-third of the soluble fiber.

Other than the solubility, the content of pentose sugars in the fiber is considered as another factor to determine the efficacy of fibers. Pentose sugars consumption is positively related to the increase in fecal weight. Fibers with rich in mannose and glucose densities, that to mannose obtained from insoluble and glucose from soluble nonstarch polysaccharides provide better protection than any other fibers. Therefore, it can be concluded that different dietary fibers on behalf of their composition offer a different extent of protection against cancer.

Antioxidant Model

As the name suggests, the model is focused on the mechanism of antioxidants present in the whole grains. The antioxidant components work by either delaying the onset of oxidation or decreasing the rate of oxidation of oxidizable substrates.

The antioxidant compounds which show protection against cancers are:

1. Vitamin E especially tocotrienols^[5]
2. Selenium which varies with soil^[5]

Trace minerals such as copper, zinc, and manganese. These are found in the outer layers of grains. Therefore, milled grains are found to be short in the amount of trace minerals

Phenolic acids. Highest in amount and found in bran layer of grains. The potency of different phenolic acids as antioxidants has been found in the particular defined order:

• Protocatechuic acid> Chlorogenic acid> gentisic acid> ferulic acid> vanillic acid> syringic acid> p-coumaric acid
• Among this, ferulic acid is found as the richest in the content of phenolic acids.
• Phytic acid. In earlier times, it was considered as antinutrient because of its tendency to bind with minerals.^[5] Wheat, corn, rice, barley, and oats are considered as rich sources of phytic acids

Lignan And Phytoestrogen Model

Adlercreutz^[5] gave the hypothesis that hormonally active compounds such as lignans and phytoestrogens can protect against the hormonally mediated diseases. Lignans are easily identifiable in the urine, blood, bile, and feces of humans. As per rat and human studies^[5] the conversion of plant lignans into mammalians lignans depends on the presence of intestinal bacteria.

An indirect method of measuring the number of lignans in the food is to measure urinary lignan excretion^[5], which increases in the grains and other high fiber foods. The primary precursor of lignan, i.e., linseed (flaxseed) consumption yields 800µg of lignans (enterolactone and enterodiol) in urine when added as per gram in the meal whereas other grains generally produces 8 to 2 µg/g meal. Other than this, berries, fruits, vegetables, and individual other seeds are considered as the significant precursors of lignans.

After going through the dietary recommendations and the various case studies, we can say that it’s not the only single food ingredient or the nutrients individually can decide the progression of disease in the lifestyle of a person. The composition of the full diet where the efficacy of every nutrient depends on the presence of other components can be used as the complete guide for the recommendations to prevent chronic diseases. Moreover, we could easily correlate the connection of nutrients with the occurrence or progression of chronic disease. Consumption of whole grains and low dietary protein in the diet will reduce the chances or severity of renal, cardiovascular, and carcinogenic diseases.

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