Many nutrients in food promote health and protect your body from disease.

Eating whole, nutritious foods is important because their unique substances work synergistically to create an effect that can’t be replicated by taking a supplement.

Vitamins and minerals

Although your body only needs small amounts of vitamins and minerals, they’re vital for your health.

However, Western diets — high in processed foods and low in whole foods like fresh produce — are typically deficient in vitamins and minerals. Such deficiencies can substantially increase your risk of disease (1).

For example, insufficient intakes of vitamin C, vitamin D, and folate may harm your heart, cause immune dysfunction, and increase your risk of certain cancers, respectively (2, 3, 4).

Beneficial plant compounds

Nutritious foods, including vegetables, fruits, beans, and grains, boast numerous beneficial compounds, such as antioxidants.

Antioxidants protect cells from damage that may otherwise lead to disease (5).

In fact, studies demonstrate that people whose diets are rich in polyphenol antioxidants have lower rates of depression, diabetes, dementia, and heart disease (6, 7, 8, 9).

Fiber

Fiber is an essential part of a healthy diet. It not only promotes proper digestion and elimination but also feeds the beneficial bacteria in your gut (10).

Thus, high-fiber foods like vegetables, beans, grains, and fruits help protect against disease, decrease inflammation, and boost your immune system (11).

On the other hand, low-fiber diets are associated with an increased risk of illnesses, including colon cancer and stroke (12, 13, 14, 15).

Protein and healthy fats

The protein and fat in whole, nutritious foods play various critical roles in your body.

Amino acids — the building blocks of protein — aid immune function, muscle synthesis, metabolism, and growth, while fats provide fuel and help absorb nutrients (16, 17).

Omega-3 fatty acids, which are found in foods like fatty fish, help regulate inflammation and are linked to improved heart and immune health (18).

Summary Whole, nutritious foods boast vitamins, minerals, antioxidants, fiber, protein, and fat, all of which promote health and are key to optimal bodily function.

Notably, nutritious foods may decrease your risk of disease — while the opposite is true for highly processed foods.

Unhealthy food choices can increase disease risk

Unhealthy diets high in sugary drinks, fast food, and refined grains are a main contributor to conditions like heart disease, diabetes, and obesity.

These processed foods harm your gut bacteria and promote insulin resistance, chronic inflammation, and overall disease risk (19).

A study in over 100,000 people found that every 10% increase in ultra-processed food intake resulted in a 12% increase in cancer risk (20).

Additionally, a study on worldwide mortality and disease showed that in 2017, 11 million deaths and 255 million disability-adjusted life years (DALYs) were likely due to poor diet (21).

DALYs measure the burden of disease, with one unit representing the loss of one year of full health (22).

Nutritious diets protect against disease

On the other hand, research indicates that diets abundant in plant foods and low in processed products strengthen your health.

For instance, the Mediterranean diet, which is rich in healthy fats, whole grains, and vegetables, is linked to a reduced risk of heart disease, neurodegenerative conditions, diabetes, certain cancers, and obesity (23, 24, 25).

Other eating patterns shown to safeguard against disease include plant-based, whole-food-based, and paleo diets (26, 27).

In fact, some diets may reverse certain conditions.

For example, plant-based diets have been found to reverse coronary artery disease while very-low-carb lifestyles may help eliminate type 2 diabetes in some people (28, 29).

What’s more, nutritious eating patterns like the Mediterranean diet are tied to better self-reported quality of life and lower rates of depression than typical Western diets — and may even boost your longevity (30, 31, 32).

Such findings prove that robust diets indeed function as preventative medicine.

Summary Following a healthy diet can increase longevity, protect against disease, and improve your overall quality of life.

While some dietary choices can either prevent or increase your disease risk, not all diseases can be prevented or treated through diet alone.

Many other factors affect your health and disease risk

Disease risk is quite complex. Although a poor diet can cause or contribute to illnesses, many other factors need to be considered.

Genetics, stress, pollution, age, infections, occupational hazards, and lifestyle choices — such as lack of exercise, smoking, and alcohol use — also have an effect (33, 34, 35, 36).

Food cannot compensate for poor lifestyle choices, genetic disposition, or other factors related to disease development.

Food should not be used as a replacement for medicine

Though shifting to a healthier dietary pattern can indeed prevent disease, it’s critical to understand that food cannot and should not replace pharmaceutical drugs.

Medicine was developed to save lives and treat diseases. While it may be overprescribed or used as an easy fix for dietary and lifestyle problems, it’s oftentimes invaluable.

As healing does not hinge solely on diet or lifestyle, choosing to forgo a potentially life-saving medical treatment to focus on diet alone can be dangerous or even fatal.

Beware of false advertising

While scientific evidence shows that food can aid various health conditions, anecdotal claims of curing or treating diseases through extreme dieting, supplements, or other methods are often false.

For example, diets advertised to cure cancer or other serious conditions are typically not backed by research and often prohibitively expensive.

Eschewing conventional treatments like chemotherapy for alternative, unproven diets can worsen diseases or lead to death (37, 38, 39).

Summary Although many foods have strong disease-fighting benefits, diet should not be considered a replacement for conventional medicine.

Transitioning to a diet based on whole foods can improve your health in countless ways. Foods that offer particularly powerful benefits include:

• Berries. Numerous studies have found that nutrients and plant compounds in berries combat disease. In fact, diets rich in berries may protect against chronic conditions, including certain cancers (40).
• Cruciferous vegetables. Cruciferous vegetables like broccoli and kale contain a wide array of antioxidants. High intake of these vegetables may decrease your risk of heart disease and promote longevity (41).
• Fatty fish. Salmon, sardines, and other fatty fish fight inflammation due to their high levels of omega-3 fatty acids, which also protect against heart disease (42).
• Mushrooms. Compounds in mushrooms, types of which include maitake and reishi, have been shown to boost your immune system, heart, and brain (43).
• Spices. Turmeric, ginger, cinnamon, and other spices are packed with beneficial plant compounds. For example, studies note that turmeric helps treat arthritis and metabolic syndrome (44, 45).
• Herbs. Herbs like parsley, oregano, rosemary, and sage not only provide natural flavor to dishes but also boast many health-promoting compounds (44).
• Green tea. Green tea has been thoroughly researched for its impressive benefits, which may include reduced inflammation and lower disease risk (46).

Nuts, seeds, avocados, olive oil, honey, seaweed, and fermented foods are just a few of the many other foods studied for their medicinal properties (47, 48, 49, 50, 51, 52).

Simply transitioning to a diet rich in whole foods like fruits and vegetables is the simplest way to reap the medicinal benefits of food.

Summary Berries, cruciferous vegetables, fatty fish, and mushrooms are just a selection of the foods that offer powerful medicinal properties.

Food not only provides energy but may also act as medicine.

A nutrient-dense diet of whole foods has been shown to prevent and even treat or reverse many chronic illnesses, such as diabetes and heart disease.

Keep in mind that you should not rely on food to replace traditional medicine.