Intermittent Fasting and Cancer Metabolism:   A Four-Part Series

 Intermittent fasting (IF) has emerged as a promising dietary intervention in cancer prevention and treatment. Recent studies have shed light on the potential mechanisms by which IF may influence cancer progression and therapy outcomes.

The OutSmart Cancer® System recommends intermittent fasting for 13 hours of calorie restriction per 24 hour cycle with the appropriate assessment, monitoring and guidance of a health care provider.

PART 1 Intermittent Fasting: Mechanisms of Action

IF has been shown to modulate several key pathways involved in cancer biology:

1. Metabolic Regulation: IF can reduce circulating levels of insulin-like growth factor 1 (IGF-1), which is associated with cancer cell proliferation1. This reduction may enhance the efficacy of cancer treatments by making cancer cells more susceptible to apoptosis.
2. Autophagy Enhancement: IF induces autophagy, a cellular “housekeeping” mechanism that can selectively target and destroy cancer cells4. This process may improve the effectiveness of anticancer therapies.
3. Immune System Modulation: Fasting periods can increase the activity of natural killer (NK) cells and cytotoxic T lymphocytes, enhancing the immune response against tumors1.
4. Oxidative Stress Reduction: IF has been observed to decrease levels of proinflammatory cytokines and increase anti-inflammatory markers, creating a less favorable environment for cancer progression1.

General Tumor Growth Inhibition

Across various cancer types, IF has been observed to:

1. Alter energy metabolism of tumor cells, inhibiting their growth2.
2. Enhance antitumor immune responses2.
3. Increase cancer sensitivity to chemotherapy and radiotherapy2.
4. Reduce glucose levels in the blood, making it harder for glucose-dependent cancers to grow6.

Mechanisms of Action

The impact of IF on tumor growth is mediated through several mechanisms:

• Metabolic Switch: IF induces a state of ketosis, which can be detrimental to cancer cells that rely heavily on glucose for rapid proliferation1.
• Immune System Enhancement: Fasting increases the activity of natural killer (NK) cells and cytotoxic T lymphocytes, improving the immune response against tumors1.
• Oxidative Stress: IF can increase reactive oxygen species (ROS) in cancer cells while decreasing their antioxidant defenses, leading to increased oxidative stress and enhanced chemotherapeutic action4.
• Signaling Pathway Modulation: IF affects the IGF-1/mTOR signaling pathway, which is known to influence cancer etiology4.