Dried fruits and nuts, renowned for their abundance of nutrients and phytochemicals, exhibit compelling anticancer, anti-inflammatory, and antioxidant properties, making them pivotal in reducing cancer risk. Robust nut consumption is linked to a diminished likelihood of specific cancers, such as lung, colon, and stomach cancers. A daily intake of 25 grams of nuts is estimated to correlate with a 20% reduction in cancer-related mortality. Moreover, evidence suggests that consistent nut consumption positively influences outcomes related to colorectal, breast, and prostate cancers.
Globally, in 2020, recorded instances of new cancer cases totaled around 20 million, with nearly 10 million cancer-related deaths. Projections indicate a 48% increase by 2040, reaching 28 million new cancer cases, driven by population growth, aging, and escalating risk factors worldwide.
Embracing a healthy lifestyle, encompassing a balanced diet, physical activity, abstaining from tobacco, and maintaining a healthy weight, significantly impacts cancer prevention, with approximately 50% of cancer cases deemed preventable. Despite this, international cancer statistics reveal that up to 80% of the cancer burden in high-income countries is generally preventable, highlighting the imperative need for studying the impact of lifestyle changes, particularly dietary modifications, on cancer development and progression. Convincing evidence underscores the significant role of nutrition in cancer occurrence and advancement.
While few countries adhere to optimal cancer prevention diets, global assessments using a healthy nutrition index expose suboptimal levels, primarily due to elevated consumption of red meat, added sugars, and trans fats, coupled with inadequate intake of fruits, vegetables, nuts, and whole grains. Inadequate diets contribute to an estimated 1.5 million preventable cancer-related deaths annually.
Reputable health organizations universally recommend heightened fruit consumption for cancer prevention and mitigating chronic disease risks. The International Agency for Research on Cancer/World Health Organization (IARC/WHO) attributes about 5% of cancer-related deaths in the United States to insufficient fruit and vegetable intake. U.S. dietary guidelines advocate for 2 cups of fruit daily in a 2000-calorie diet, with half a cup of dried fruit equating to one cup. The U.S. Food and Drug Administration (FDA) permits claims about fruit and cancer, emphasizing the potential risk reduction associated with adopting a low-fat diet rich in fruits and vegetables.
IARC/WHO recommends the consumption of whole grains, legumes, vegetables, and fruits for cancer prevention. Tree nuts and peanuts are widely endorsed as nutritious foods, with the Global Cancer Patterns report associating diets rich in fruit and nuts with a reduced risk of colorectal cancer. Various agencies underscore the significance of dietary bioactives in cancer prevention.
Globally, common dried fruits encompass raisins, dates, prunes, apricots, and figs. Specialty dried fruits like sweet cherries, high-value frozen fruit, and powders also exist. Dried fruit consumption is prominent in the Middle East and Europe, comprising half of global consumption, whereas in the United States, dried fruits constitute less than 5% of total fruit consumption.
Cancer, a complex malady, can be influenced through various mechanisms. Preclinical studies propose that dried fruits may deter cancer initiation by inducing detoxifying enzymes, reducing the impact of carcinogens, and alleviating environmental stress. In the progression stage, dried fruits may aid in inhibiting oxidative stress and inflammation, inducing apoptosis, and impacting cancer-related factors, including antioxidant and anti-inflammatory activities.
Dried fruits are replete with fiber, micronutrients, and bioactive compounds, fostering cancer prevention. Their diverse range of bioactive compounds, including phenolics, carotenoids, and terpenoids, is instrumental. The drying process can alter characteristics and bioavailability; for instance, freeze-drying may better preserve bioactive compounds compared to other methods. While the heat in drying processes can enhance certain compounds, it may also lead to the formation of advanced glycation end products (AGEs), which, despite concerns, are not conclusively linked to increased cancer risk.
Inclusion of sulfites during processing affects melanoidin formation and alters bioactive characteristics. The drying process also impacts the structure and accessibility of soluble fiber and bioactive compounds, influencing gut microbiota and immune system function. However, evidence from human intervention studies on cancer prevention with dried fruit consumption is limited, necessitating further exploration.
Epidemiological studies probing the direct link between dried fruits and cancer risk are sparse, with a systematic review revealing inconclusive evidence. While some associations exist, more comprehensive research, considering variations in composition and processing methods, is required.
While fruits are universally recommended for cancer prevention, the role and mechanisms of dried fruit consumption necessitate further elucidation. Attention to study design and identification of specific mechanisms through which dried fruits influence cancer risk are crucial. Human studies evaluating bioactives and their metabolites in tissues during dried fruit consumption are imperative for enhanced understanding and targeted dietary recommendations.
A holistic view, supported by evidence, underscores that cancer-protective diets are predominantly plant-derived, emphasizing unprocessed plant foods rich in nutrients and dietary fiber. Substituting processed and sugary foods with these options helps guard against weight-related cancers, such as breast, colorectal, liver, thyroid, pancreatic, endometrial cancers, and postmenopausal kidney cancer.
Tree nuts (almonds, hazelnuts, and walnuts) and peanuts, packed with nutrients like unsaturated fats, protein, vitamins, non-sodium minerals, potassium, and phytochemicals, exhibit anticancer, anti-inflammatory, and antioxidant properties. These foods modulate gut microbiota, contributing to potential cancer prevention. Studies suggest that walnut consumption may reduce breast tumor growth, while mixed nut consumption, including walnuts and almonds, may inhibit colorectal tumor growth and positively impact gut microbial health.
Human intervention studies reveal that mixed nut consumption, both short and long term, modulates biochemical pathways related to cancer prevention and progression. Observational studies associate daily mixed nut consumption with reduced cancer-related mortality, particularly in prostate cancer cases.
While the impact of mixed nuts on concurrent cancer and chronic disease occurrence requires further exploration, studies suggest potential benefits. In summary, the comprehensive evidence underscores the role of dried fruits and nuts in cancer prevention, emphasizing the need for continued research to enhance our understanding and inform dietary recommendations.