NAD stands for nicotinamide adenine dinucleotide. It’s a tiny molecule found in every cell in your body. NAD helps your cells make energy by carrying electrons from one chemical reaction to another. This process powers nearly everything your body does, and it keeps your cells working properly as you get older.

NAD exists in two main forms:

• NAD+: NAD+ is the “oxidized” form. It’s sometimes called the “empty” form because it’s ready to accept electrons during chemical reactions.
• NADH: NAD with hydrogen is the “reduced” form. It’s considered the “full” form because it’s carrying electrons that can be used to make energy.

Together, NAD+ and NADH act like a shuttle. They move electrons back and forth so your body can turn food into energy. This constant cycling helps keep energy flowing inside your cells.

Your body makes NAD using building blocks called precursors. These include forms of vitamin B3 (like niacin) and the amino acid tryptophan. Your cells can create NAD from scratch or recycle it from smaller molecules. Enzymes — proteins that drive chemical reactions — help keep this process running. If these enzymes don’t work properly, NAD levels can drop. This can affect energy production and overall cell health.

What are the functions of nicotinamide adenine dinucleotide?

One of NAD’s most important roles is helping to convert the food you eat into usable energy. This process happens largely in the mitochondria, often called the “powerhouse” of the cell.

NAD also supports several other key functions, including:

• DNA repair: NAD helps enzymes fix damage to your genetic material.
• Metabolism: It supports chemical reactions that break down nutrients.
• Cell protection: NAD helps limit harmful byproducts that can build up when cells are under stress.
• Teamwork: It supports the normal function of your muscles, brain cells, heart cells and bones.

What are the parts of NAD?

NAD is made up of three main parts:

• Nicotinamide: This portion accepts and donates electrons. It’s the part that switches between NAD+ and NADH.
• Adenine: This is a molecule also found in DNA. It helps NAD interact with enzymes inside cells.
• Two sugar-phosphate groups: These connect nicotinamide and adenine, forming the structure of the molecule.

What is the relationship between nicotinamide adenine dinucleotide and aging?

NAD helps your cells work and stay healthy. As you age, NAD levels naturally decline. Some cells begin using NAD more quickly than your body can replace it, lowering overall levels.

With less NAD available, cells may have a harder time making energy and repairing damage. Lower NAD levels have been linked to age-related changes, including:

• Muscle weakness and fatigue
• Eye conditions, like vision loss and glaucoma
• Metabolic disorders, including Type 2 diabetes and obesity
• Heart issues, like arrhythmia and heart failure
• Cognitive decline, including slower thinking and memory loss

Researchers continue to study how NAD levels may affect aging. Supporting NAD production may help maintain cell function over time.

What foods help your body make nicotinamide adenine dinucleotide?

Food doesn’t contain meaningful amounts of NAD directly. Instead, your body makes NAD from certain nutrients found in food. These include vitamin B3 (niacin) and the amino acid tryptophan.

Foods that contain vitamin B3 include:

• Meat (chicken, turkey, beef)
• Fish (tuna, salmon)
• Whole grains
• Legumes (beans, lentils)
• Nuts

Foods that contain tryptophan include:

• Turkey and chicken
• Eggs
• Dairy (milk, cheese, yogurt)
• Soy products
• Nuts and seeds

Eating foods rich in these nutrients helps support your body’s natural ability to make NAD.

What other ways can you support healthy NAD levels?

In addition to eating foods high in vitamin B and tryptophan, you may be able to support balanced NAD levels by:

• Getting regular physical activity
• Managing stress
• Staying socially and mentally active
• Limiting alcohol consumption
• Getting enough sleep

Research is ongoing on the effectiveness of NAD+ supplements. They may help restore energy and cell repair as you age, but more studies are needed.