Grapes And Health: Research Findings

By Kathleen Nave, President, California Table Grape Commission

When it comes to produce and health, the evidence of benefits is overwhelming, and the role of fruits and vegetables in promoting health is recognized by major public health entities and advocacy groups worldwide. Within the produce industry, much effort has gone into better defining and understanding those benefits with new findings emerging on a regular basis that reinforce the promise of produce.

For nearly 20 years, the California table grape industry has supported research into the health benefits of grapes. The program was created to better understand the beneficial compounds in grapes that could play a role in health and disease prevention, as well as to help build the body of scientific evidence on grapes and health. The program funds investigator-initiated studies on a wide range of topics, all of which are run independently of Commission involvement. The researchers are free to publish their findings, no matter what the study outcome. The result has been strong interest by the research community nationwide to apply for and conducts research on grapes and health.

Most recently, a newly published study heralded new hope in the area of brain health: a grape-enriched diet was shown to protect against metabolic brain decline in Alzheimer’s-related areas of the brain. Specifically, in a pilot study of people with early memory decline, subjects were either fed whole grape powder equivalent to just 2 ¼ cups of grapes per day or a placebo powder. The results showed that consuming grapes preserved healthy metabolic activity in regions of the brain associated with early Alzheimer’s disease, where metabolic decline takes hold. Subjects who didn’t consume grapes exhibited a significant metabolic decline in these critical regions. Additionally, those consuming the grape-enriched diet showed beneficial changes in regional brain metabolism that correlated to improvements in cognition and working memory performance.

While research in the area of grapes and brain health is emerging, the evidence surrounding grapes and heart health is well-established, including the protective effects of grape polyphenols against the development of atherosclerosis. Heart-healthy grapes may also play a role in healthy aging as presented in the chapters of a recently published monograph titled, Grapes and Health, which covers a broad range of grape research conducted on relevant health issues, including:

Inflammation — Intake of grape products can help modify both local and systemic inflammation by acting in a variety of ways that go beyond antioxidant effects. Inflammation plays a critical role in most chronic diseases, so the ability to modulate inflammation has far-reaching implications.

Cancer — A high intake of fruits and vegetables is associated with disease prevention, and grapes are a food that should be included in a healthy diet. Many studies have been conducted to evaluate the potential for grapes and grape products to inhibit cancer, with intriguing results in the area of colon cancer.

GI Health — The link between intestinal health and overall health is an exciting new field of research. Polyphenols may influence nutrient absorption and intestinal bacteria and their fermentation products; since they are not well absorbed in the upper GI tract, they do arrive in the colon where they have been shown to influence microbial growth and metabolism.

Brain Health — Various grape products have been studied and shown to reduce symptoms of post-traumatic stress disorder, including anxiety, depression and memory loss; and improve learning and memory in mice with Alzheimer’s and in animals exposed to stress, aging, and disease.

Joint Health — Grapes have been shown to exert a beneficial effect in osteoarthritis and some inflammatory arthritis forms, including rheumatoid arthritis.

Bladder Health — A series of animal studies have shown a grape-enriched diet protects the bladder from dysfunction associated with partial bladder outlet obstruction. In humans, more than 80 percent of men older than 50 are affected by this issue due to an enlarged prostate gland. Grapes provide an antioxidant effect that helps counter the damaging effects of oxygen deprivation and a free radical generation that occur and disrupt normal cell function, ultimately injuring the nerves and smooth muscle cells in the bladder wall.

Eye Health —Grapes may contribute to eye health by promoting antioxidant actions that protect the retina’s structure and function; preventing activation of inflammatory pathways and inhibiting abnormal and harmful blood vessel growth in the eye.

Just as science has made clear the health benefits provided by daily consumption of a mix of fruits and vegetables, it is making clear the broad-scale benefits consumption of fresh grapes provides. This growing evidence reinforces the benefits of produce intake generally. The fact that grapes are a favorite fruit for consumers of all ages and they are readily available — California’s season is May through January — makes adding them to the list of items eaten on a regular, or maybe even on a daily basis, easy.

The California Table Grape Commission was established by an act of the state’s legislature in 1967. Approved by a grower referendum in 1968, the commission has been affirmed through grower referenda every five years since its inception. The commission’s importance to the state and its mandate – to maintain and expand markets for fresh California grapes and to create new and larger intrastate, interstate and foreign markets – was reaffirmed and its authorities broadened by the legislature in 1995, 1997 and again in 2001. The commission’s activities are divided into five areas: research, trade management, issue management, education and outreach, and advertising.