Nicotine changes marijuana's effect on the brain

Date: August 18, 2015

Source: Center for BrainHealth

Summary:

How scientists study the effects of marijuana on the brain is changing. Until recently marijuana research largely excluded tobacco users from its participant pool, but scientists have found reason to abandon this practice, uncovering significant differences in the brains of individuals who use both tobacco and marijuana and the brains of those who only use marijuana.

This is Dr. Francesca Filbey, study principal investigator and Director of Cognitive Neuroscience of Addictive Behaviors at the Center for BrainHealth at The University of Texas at Dallas

Credit: Randy Anderson

How scientists study the effects of marijuana on the brain is changing. Until recently marijuana research largely excluded tobacco users from its participant pool, but scientists at the Center for BrainHealth at The University of Texas at Dallas have found reason to abandon this practice, uncovering significant differences in the brains of individuals who use both tobacco and marijuana and the brains of those who only use marijuana.

In a study that appears online in the journal Behavioural Brain Research, scientists report an association between smaller hippocampal brain volume and marijuana use. Although the size of the hippocampus, an area of the brain associated with memory and learning, is significantly smaller in both the marijuana group and marijuana plus tobacco group compared to non-using controls and individuals who use tobacco exclusively, the relationship to memory performance is unique.

Hippocampal size of nonusers reflects a direct relationship to memory function; the smaller the hippocampus, the poorer the memory function. Individuals who use marijuana and tobacco show an inverse relationship, i.e., the smaller the hippocampus size, the greater memory the function. Furthermore the number of nicotine cigarettes smoked per day in the marijuana and nicotine using group appears to be related to the severity of hippocampal shrinkage. The greater the number of cigarettes smoked per day, the smaller the hippocampal volume and the greater the memory performance. There were no significant associations between hippocampal size and memory performance in individuals who only use tobacco or only use marijuana.

"Approximately 70% of individuals who use marijuana also use tobacco," explained Francesca Filbey, Ph.D., the study's principal investigator and Director of Cognitive Neuroscience of Addictive Behaviors at the Center for BrainHealth. "Our findings exemplify why the effects of marijuana on the brain may not generalize to the vast majority of the marijuana using population, because most studies do not account for tobacco use. This study is one of the first to tease apart the unique effects of each substance on the brain as well as their combined effects."

Dr. Filbey's research team used magnetic resonance imaging (MRI) to examine the hippocampus; an area of the brain that is know to have altered size and shape in association with chronic marijuana use. Participants completed a substance use history assessment and neuropsychological tests three days prior to an MRI head scan. The team compared four groups: nonusers (individuals who have not had any marijuana or tobacco in the past three months), chronic marijuana users (individuals who use marijuana at least four times per week), frequent nicotine users (10 or more times daily) and chronic marijuana plus frequent nicotine users (at least four marijuana uses per week and 10 or more nicotine uses per day).

"We have always known that each substance is associated with effects on the brain and hypothesized that their interaction may not simply be a linear relationship. Our findings confirm that the interaction between marijuana and nicotine is indeed much more complicated due to the different mechanisms at play," said Filbey. "Future studies need to address these compounding effects of substances."

She continued, "The combined use of marijuana and tobacco is highly prevalent. For instance, a 'blunt' is wrapped in tobacco leaf. A 'spliff' is a joint rolled with tobacco. We really need to understand how the combined use changes the brain to really understand its effects on memory function and behavior."

Story Source:

The above post is reprinted from materials provided by Center for BrainHealth. Note: Materials may be edited for content and length.

Journal Reference:

Francesca M. Filbey, Tim McQueeny, Shrinath Kadamangudi, Collette Bice, Ariel Ketcherside. Combined effects of marijuana and nicotine on memory performance and hippocampal volume. Behavioural Brain Research, 2015; 293: 46 DOI: 10.1016/j.bbr.2015.07.029

Cite This Page:

Center for BrainHealth. "Nicotine changes marijuana's effect on the brain." ScienceDaily. ScienceDaily, 18 August 2015. <www.sciencedaily.com/releases/2015/08/150818142415.htm>.

Five reasons why sugar is added to food

Date: August 18, 2015

Source: Institute of Food Technologists (IFT)

Summary:

From a food science and technology perspective, sugar (sucrose) plays several roles when it comes to the functional properties in food. Experts explain the functional properties of sugars and why they are often added to foods.

From a food science and technology perspective, sugar (sucrose) plays several roles when it comes to the functional properties in food. In the September issue of Comprehensive Reviews in Food Science and Food Safety published by the Institute of Food Technologists (IFT), authors from the University of Minnesota write about the functional properties of sugar and why they are often added to foods.

1. Taste: Sweetness improves the palatability of many foods. Adding sugar to foods with high nutrient quality may increase the chance they are consumed. In addition, sugar plays an important role in contributing to the flavor profile of foods by interacting with other ingredients to enhance or lessen certain flavors.

2. Color and Flavor: The Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavor; and caramelization is fundamental to the formation of color in several food products and can't happen without the addition of sugar. Caramelization happens when sugar is heated to a certain temperature and is used in a wide variety of products including sauces, candies, breads, jams, and dessert wine (Kroh, 1993). The Maillard reaction also provides desirable flavor formation in foods such as baked goods, chocolate, coffee and meat (Danehy and Wolnak, 1983).

3. Bulk and Texture: Sugar provides bulk to foods which impacts the mouthfeel and texture. Sugar affects multiple chemical reactions that form the texture of baked goods, ice cream, candies, and jams, preserves and jellies.

4. Fermentation: Fermentation is a process in which microorganisms in the absence of oxygen generate energy by oxidizing carbohydrates, like sugar. Sugar aids in the fermentation of many common food and beverage products produced including yogurt, vinegar, sour cream, wine, beer, bread, cheese, soy sauce, and sauerkraut.

5. Preservation: The hygroscopic nature of sugar plays a crucial role in reducing water activity in foods. Hygroscopic is defined as the ability to absorb water from the surrounding environment which helps in preserving and extending the shelf-life of food products (Kitts, 2010). Sugar also prevents baked good from becoming dry or stale (Spillane, 2006) and it also preserves the color of frozen fruits and jellies.

This article in Comprehensive Reviews in Food Science and Food Safety also discusses the challenges of labeling added sugar and the technical issues associated with replacing added sugar in foods.

Story Source:

The above post is reprinted from materials provided by Institute of Food Technologists (IFT). Note: Materials may be edited for content and length.

Journal Reference:

Kara R. Goldfein, Joanne L. Slavin. Why Sugar Is Added to Food: Food Science 101. Comprehensive Reviews in Food Science and Food Safety, 2015; DOI: 10.1111/1541-4337.12151

Cite This Page:

Institute of Food Technologists (IFT). "Five reasons why sugar is added to food." ScienceDaily. ScienceDaily, 18 August 2015. <www.sciencedaily.com/releases/2015/08/150818131807.htm>.