Antitumor Activity of Yogurt Components ¹

Area of Science:

• Oncology
• Nutrition Science
• Microbiology

Background:

• Ehrlich ascites tumor is a model for studying cancer progression.
• Dietary components, including fermented dairy products, are investigated for their potential health benefits.
• Yogurt contains various bioactive compounds that may influence cellular processes.

Purpose of the Study:

• To investigate the effect of yogurt consumption on Ehrlich ascites tumor growth in a mouse model.
• To determine the specific components of yogurt responsible for any observed antitumor activity.
• To assess the impact of yogurt feeding timing and duration on tumor inhibition and survival.

Main Methods:

• Male Swiss mice were inoculated with Ehrlich ascites tumor cells.
• Mice were fed either yogurt or yogurt components ad libitum.
• Tumor cell counts and DNA synthesis were measured.
• Yogurt was fractionated into solids and supernatant for activity assessment.
• Feeding was initiated at different time points relative to tumor implantation.

Main Results:

• Yogurt feeding for 7 days post-implantation significantly inhibited tumor cell counts (24-28%) and DNA synthesis (23-31%).
• Milk or lactic acid alone did not show significant inhibitory effects.
• The antitumor activity was localized in the solids fraction of yogurt; the supernatant had no activity.
• Initiating yogurt feeding more than 1 day after tumor implantation reduced the inhibitory effect.
• Continuous yogurt feeding from day 1 until death did not significantly affect mouse survival rates.

Conclusions:

• Yogurt possesses antitumor activity against Ehrlich ascites tumor in mice, primarily attributed to its solids fraction.
• The timing of yogurt consumption is crucial for achieving significant tumor growth inhibition.
• While yogurt can inhibit initial tumor development, it does not enhance survival rates in this model.