Plant-Based Diets: Health Benefits, Nutritional Value

A plant-based diet is often touted as the healthiest approach to eating, and its benefits extend way beyond weight loss. Research indicates that a plant-based diet consisting of unrefined plant-based foods is the cornerstone of healthy longevity and may be the most important prescriptive tool to help patients achieve a longer life and better quality of life as they age. Plant-based diets are associated with a lower risk of developing coronary heart disease, high blood pressure, diabetes, certain cancers, and improved cholesterol levels. Plant-based diets are also associated with lower systolic and diastolic blood pressure.

Lower blood pressure

Hypertension, or high blood pressure, is a deadly disease that affects over one billion people worldwide. It is often detected incidentally and can lead to heart failure, stroke, and renal disease. A plant-based diet has been shown to be an effective intervention for lowering blood pressure and is even more important than exercise and weight loss.

Research and Studies

A small cross-sectional study compared the blood pressure of sedentary vegans, endurance athletes consuming a Western diet, and sedentary subjects consuming a Western diet. The results showed that blood pressure was significantly lower in the vegan group, even when compared to the endurance athletes.

The first major randomized controlled trial to evaluate diet and hypertension was the Dietary Approaches to Stop Hypertension (DASH) study in the mid-1990s. The DASH diet, which is high in fruits and vegetables and low in saturated and total fat, reduced systolic and diastolic blood pressure by 5.5 mmHg and 3.0 mmHg, respectively, compared to a control diet.

The Adventist Health Study-2 (AHS-2) found that vegans and lacto-ovo vegetarians had significantly lower systolic and diastolic blood pressure and a lower odds of hypertension compared to non-vegetarians.

Mechanisms

There are several proposed mechanisms by which a plant-based diet leads to a decrease in blood pressure:

• Improved vasodilation
• Greater antioxidant content and anti-inflammatory effects
• Improved insulin sensitivity
• Decreased blood viscosity
• Modifications in the renin-angiotensin and sympathetic nervous systems
• Modification of the gut microbiota

A plant-based diet has been shown to be an effective intervention for lowering blood pressure and preventing and treating hypertension. It is important to note that a well-balanced plant-based diet is necessary to ensure adequate nutrient intake and prevent potential deficiencies.

Reduce risk of heart disease

According to the World Health Organization, cardiovascular disease is the leading cause of death in the United States and worldwide. Research shows that a plant-based diet can not only prevent heart disease but also manage and sometimes even reverse it.

A plant-based diet is beneficial for heart health because it contains no dietary cholesterol, very little saturated fat, and abundant fiber. On the other hand, meat, cheese, and eggs are packed with cholesterol and saturated fat, which cause plaque buildup in the arteries, eventually leading to heart disease.

A plant-based diet can also help improve several risk factors for heart disease, including high blood pressure, high cholesterol, inflammation, and excess weight.

Pioneering studies by Dean Ornish, MD, and Caldwell Esselstyn Jr., MD, have shown that a low-fat, plant-based diet, combined with regular exercise and a healthy overall lifestyle, can prevent, delay, and even reverse heart disease and other cardiovascular events.

In Dr. Ornish's landmark study, participants with moderate to severe heart disease were placed on a plant-based diet with no surgeries or stents. Within weeks, 90% of chest pain diminished, and after just one month, blood flow to the heart improved. After a year, even severely blocked arteries had reopened.

Dr. Esselstyn tested a similar approach on patients with severe heart disease at the Cleveland Clinic and published similar results, finding that the narrowing of the arteries was reduced, resulting in improved blood flow to the heart. Thirty years later, all the compliant patients are still thriving.

To improve heart health, replace meat with beans, tofu, tempeh, or lentils. Aim for at least two servings of fruit and three servings of vegetables daily. Keep your saturated fat intake as low as possible by avoiding animal products, ultra-processed foods, and tropical oils, such as coconut oil and palm oil.

Neal Barnard, MD, FACC, and President of the Physicians Committee, states:

> "If you change your diet, and do it very vigorously, you have enormous power. You can reverse heart disease. You can prevent it."

The American Heart Association also highlights the importance of eating more fruits and vegetables to lower the risk of heart attacks and other types of cardiovascular disease.

There are several types and variations of plant-based diets to choose from, depending on your lifestyle and personal preferences:

• Vegans: Do not consume any animal products, including dairy and eggs.
• Ovo-vegetarians: Consume eggs but not other animal foods, including dairy.
• Lacto-vegetarians: Consume dairy foods but not eggs, meat, poultry, and seafood.
• Lacto-ovo-vegetarians: Consume dairy foods and eggs but not meat, poultry, or seafood.
• Pescatarians: Consume fish and/or shellfish.
• Semi-vegetarians (or flexitarians): Occasionally consume meat or poultry.

Lower risk of type 2 diabetes

Plant-based diets are gaining popularity as people are choosing to reduce or eliminate animal products from their diets. Research has shown that these diets are cost-effective, low-risk interventions that may lower body mass index, blood pressure, HbA1C, and cholesterol levels, and may also reduce the number of medications needed to treat chronic diseases. Plant-based diets have also been shown to lower the risk of developing type 2 diabetes.

Plant-Based Diets and Type 2 Diabetes

Large cohort studies have shown that the prevalence and incidence of type 2 diabetes are significantly lower among those following plant-based eating patterns compared to omnivores and even semi-vegetarians. This is partly due to the fact that those following plant-based diets tend to have lower body mass indices, which protects against type 2 diabetes. However, differences in diabetes risk persist even after adjustments for adiposity.

Components of Plant-Based Diets and Type 2 Diabetes

A whole-foods, plant-based eating pattern generally includes legumes, whole grains, fruits, vegetables, and nuts, and is high in fiber. All of these elements have been found to be protective against diabetes. Diets based on whole plant foods not only maximize protective foods but also exclude key animal-based foods that tend to promote insulin resistance, particularly processed and unprocessed red meat.

Plant-Based Diets for the Treatment of Type 2 Diabetes

Plant-based diets, particularly vegan diets, improve glycemic control, body weight, and cardiovascular risk factors in individuals with type 2 diabetes. Each of these is central to diabetes management. Plant-based diets may also improve β-cell function, which is impaired in type 2 diabetes pathophysiology.

Mechanisms of Plant-Based Diets and Type 2 Diabetes

Insulin resistance and subsequent impairment in β-cell function are the hallmarks of type 2 diabetes pathophysiology. Plant-based eating patterns are beneficial for patients with diabetes by improving insulin sensitivity and improving body weight. Insulin resistance is caused by lipid accumulation within muscle and liver cells that typically begins many years before the diagnosis of type 2 diabetes. This lipid accumulation is highly responsive to diet changes. High-fat diets downregulate the genes required for mitochondrial oxidative phosphorylation in skeletal muscle and appear to disrupt the normal intestinal barrier to bacterial endotoxins, which can disrupt glucose oxidation processes.

Practical Considerations for Plant-Based Diets and Type 2 Diabetes

Health care providers should feel confident in counseling their patients to follow a plant-based eating pattern and should be prepared to provide education and support to improve their patients' diabetes outcomes, general health, and psychological well-being. Patients are typically willing to try a plant-based diet when its rationale has been explained, and they can adapt nutrition guidelines to suit their preferences. Further, the acceptability of a low-fat plant-based diet has been shown to be comparable to other therapeutic eating patterns in randomized trials with individuals with diabetes.

Weight loss

Adopting a plant-based diet can be an effective way to lose weight. Research has shown that people who follow a plant-based diet tend to weigh less. This is because whole grains and vegetables are relatively low on the glycemic index, meaning they are digested more slowly, and fruits contain antioxidants and fibre, which helps prolong fullness.

A study by Berkow and Barnard reviewed data from 87 published studies and reported that a vegan or vegetarian diet is highly effective for weight loss. They also found that vegetarian populations have lower rates of heart disease, high blood pressure, diabetes, and obesity. In addition, their review suggests that weight loss in vegetarians is not dependent on exercise and occurs at a rate of approximately 1 pound per week.

Farmer et al. suggest that vegetarian diets may be better for weight management and may be more nutritious than diets that include meat. In their study, they showed that vegetarians were slimmer than their meat-eating counterparts. Vegetarians were also found to consume more magnesium, potassium, iron, thiamin, riboflavin, folate, and vitamins and less total fat.

A small study found that 65 overweight adults who followed a whole-food, plant-based diet for one year lost 9.25 pounds on average. Plus, this diet was not calorie-restricted; the participants were allowed to eat what they wanted and still lost weight.

A plant-based diet can also help with weight loss because it is not just a diet, but a general approach to eating. There is no need to count calories or stress about meeting certain macronutrient goals each day. It is simply about eating more plant-based foods and fewer animal-based ones.

A plant-based diet can also help with weight loss by improving your cholesterol levels. High cholesterol can lead to fatty deposits in the blood, which can restrict blood flow and potentially lead to heart attack, stroke, or heart disease. However, a healthy diet can help keep cholesterol levels in check. Specifically, moving away from a diet filled with animal products toward one that’s primarily plant-based can lower LDL (“bad”) cholesterol by between 10 and 15 percent, while those following a strict vegan diet can lower their LDL cholesterol by as much as 25 percent.

In addition, a plant-based diet can help with weight loss by reducing your risk of developing type 2 diabetes. Weight is a major risk factor for type 2 diabetes since more fatty tissue makes the cells more resistant to insulin. However, a plant-based diet filled with high-quality plant foods can reduce the risk of developing type 2 diabetes by 34 percent. This is because plants are lower in saturated fats than animal foods, which raises cholesterol levels and your risk of developing type 2 diabetes.

Finally, a plant-based diet can help with weight loss by lowering your risk of developing certain types of cancer. The American Institute for Cancer Research says that the best way to source cancer-protective nutrients, including fibre, vitamins, minerals, and phytochemicals, is to eat a diet rich in vegetables, fruit, grains, beans, nuts, seeds, and some animal foods. Research suggests that following a plant-based diet may help prevent cancer by providing the body with these cancer-protective nutrients.

Lower cholesterol

High cholesterol is a causal risk factor for heart disease. A plant-based diet is an effective way to optimise your cholesterol levels. Cholesterol is a waxy substance produced by the liver that aids in building cell membranes and producing hormones. While cholesterol is important, our bodies naturally produce enough to meet our needs, so we don't need to consume extra cholesterol through our diets.

Cholesterol needs to be transported through the bloodstream. To do this, it is packed into two types of carriers: low-density lipoproteins (LDL) or high-density lipoproteins (HDL). LDL cholesterol, or "bad cholesterol", is necessary in limited quantities, but high levels can dramatically increase your risk of a heart attack. This is because LDL particles can contribute to plaque formation in the arteries. HDL cholesterol, or "good cholesterol", helps to clear LDL cholesterol from the arteries.

Factors that can negatively impact HDL include a diet high in saturated fat, smoking, alcohol intake, obesity, and lack of exercise. Vigorous exercise and adding omega-3 fats in place of saturated fats may help to increase HDL levels.

The American Heart Association (AHA) recommends that people aim for a total cholesterol level below 150 mg/dL, with LDL cholesterol at or below 100 mg/dL. However, even "normal" cholesterol levels may not be enough to prevent heart disease. Research suggests that an LDL cholesterol of around 50-60 mg/dL offers the most protection against cardiovascular events, such as heart attacks.

Plant-based diets have been found to lower cholesterol levels more effectively than other diets. In 2017, researchers reviewed nine studies that compared plant-based diets with omnivorous diets and their effects on cholesterol. They found that plant-based diets lowered total cholesterol, LDL, and HDL levels when compared to omnivorous diets. Low-fat, plant-based regimens typically reduce LDL levels by about 15-30%.

Plant-based diets tend to be higher in healthy unsaturated fats but lower in saturated fat, cholesterol, and total fat, which likely explains their effectiveness in lowering cholesterol. In addition, plant-based diets are often higher in fibre, which reduces the absorption of cholesterol from the gut and increases the amount of cholesterol excreted in the stool.

Soy consumption has been found to reduce both total and LDL cholesterol. Good sources of soy include tofu, tempeh, soy milk, and edamame. Other foods that can help lower cholesterol include oats, beans, barley, and nuts.

In addition to dietary changes, it is important to note that lifestyle factors such as exercise, avoiding tobacco, and managing stress can also help to lower cholesterol and prevent heart disease.

Frequently asked questions