How Aging Affects Nutrient Absorption: Key Deficiencies and What to Do About Them

The Impact of Aging on Nutrient Absorption

Decreased Digestive Efficiency: A Common Age-Related Change

Aging is inevitable, and as we age, it is common for our GI tracts to not function as well as they once did. Not all individuals are the same, but it is common to experience some changes in individuals with comorbidities. Often due to diet and lifestyle, these changes can impact one’s ability to digest and absorb nutrients efficiently for the body to use. Starting in the mouth, it is common in older individuals to have reduced saliva production, resulting in lower enzymatic reactions that begin the breakdown of food. Sometimes poor dental hygiene can make chewing more difficult resulting in poor digestion in the GI tract. 

Other problems can arise, such as lower gastric acid content due to chronic PPI use or viral/bacterial infections in the GI tract. Also, gut microbiome changes can create an environment susceptible to infection and GI-related problems. Meanwhile, the aging of gastrointestinal organs like the pancreas can result in lower function, affecting digestion and absorption. Many in the older population experience multiple GI-related issues, such as reflux, diarrhea, constipation, dysphagia, increased infections, and other systemic problems.

Reduced Appetite and Dietary Intake: A Risk Factor for Nutrient Deficiencies

Reduced food intake can cause physiological changes and nutrient deficiencies that can impact overall health—malnutrition results from decreased intake of calories and protein, which causes muscle deterioration for energy use. Micronutrient deficiencies can also affect overall health. Bone health and cognitive decline are both associated with limited micronutrient intake, which can result in poorer health in older people.

Key Vitamins and Minerals to Monitor

Vitamin B12: Essential for Nerve Health and Energy

Vitamin B12 is an essential micronutrient for nerve function, creating healthy red blood cells and DNA. Older adults are at an increased risk for a B12 deficiency due to multiple factors, including reduced intake of B12-rich foods, chronic PPI use that results in lower stomach acid, reduction in intrinsic factor and lower stomach acid as a result of aging, and a higher incidence of H. Pylori infections. A vitamin B12 deficiency can also go undetected for some periods due to non-specific symptoms like weakness, fatigue, dizziness, and shortness of breath.

Calcium and Vitamin D: Supporting Bone Health and Immune Function

Vitamin D and calcium are two essential micronutrients that work in harmony. Vitamin D is vital to promote calcium absorption in the small intestines, and it also helps to ensure that bones have the right amount of calcium needed for mineralization and to keep bones strong. While vitamin D deficiency is common among the majority of Americans, older individuals are at increased risk due to lower intake of vitamin D foods, limited mobility to get outside and obtain adequate sun exposure, and comorbidities like kidney disease that limit absorption of vitamin D. Individuals at with a vitamin D and calcium deficiency are at risk for secondary hyperparathyroidism, bone loss leading to increased risk for fractures, osteoporosis, and muscle weakness which can further impact quality of life.

Iron: Preventing Anemia

Iron is essential for transporting oxygen to all cells throughout the body. When iron levels are too low, anemia results in fatigue and weakness. Anemia in older people is also related to poorer quality of life, increased morbidity, and mortality.

Recognizing the Signs of Nutrient Deficiencies

Fatigue and Weakness: A Common Symptom

Fatigue and weakness are telltale signs that something may be off, especially if you notice that you or a loved one is not eating as much. As previously mentioned, not getting adequate micronutrients can affect your muscles, nervous system, and overall energy levels, making you feel extremely tired and further impacting your quality of life.

Hair Loss and Brittle Nails: Physical Signs of Deficiency

Another physical sign is changes in hair and nails. Hair loss and brittleness, dullness, or dryness can also indicate that your body is not getting adequate nutrients to maintain resilience. Your nails could become brittle and dry, or you may notice ridges indicating a nutrient deficiency. Hair loss is common in elderly populations, but this should be a sign that things may not be normal, especially if it is sudden or affects your view of yourself.

Mood Changes and Cognitive Decline: The Mental Impact of Nutrient Deficiencies

I don’t know about you, but I often feel moody or irritable if I don’t eat enough food or am hungry. Sometimes, I don’t think through things thoroughly because I am focused on hunger. This can often be a sign seen in older people that could indicate they are not eating enough. B vitamins, iron, and vitamin D, among other minerals, are essential for muscle and nerve health, and they can affect how you feel and cognition.

Strategies for Optimal Nutrient Intake

A Balanced Diet: Prioritizing Nutrient-Dense Foods

To help support your health in old age, it is important to consume a balanced diet of whole foods – fiber-rich foods like fruits, vegetables, and whole grains, lean proteins and healthy fats like chicken, breast, turkey, fish, lean grass-fed beef, beans, nuts, seeds and heart-healthy oils like olive oil are great options. To ensure you’re getting enough of these nutrients, prioritize eating protein foods first followed by the others. If eating “standard” sized meals is too much, opt for smaller, frequent meals throughout the day to make sure you get adequate protein and calories to promote nourishment.

Supplements: When They May Be Necessary

Supplements are not for everyone, but a dietary supplement might be for you if you cannot eat adequately to maintain nourishment. Before starting any supplements, always talk with your provider about laboratory testing to assess whether you need them. As with anything in life, too much of a good thing can be bad, so it’s important to consult a professional.

Here are some general guidelines for the nutrients discussed in this article.

• Vitamin D: 800 IU daily for adults over 70 years of age

• Calcium:

• Women: 1200 mg daily for women 51 years of age and older

• Men: 1000 mg daily for men 50-70 years of age and 1200 mg daily for men greater than 70 years of age

• Vitamin B12: 2.4 mcg daily

• Iron: 8 mg daily for adults 50 years of age and older

Regular Health Check-ups: Early Detection and Intervention

If you suspect you or a loved one is at risk for a nutrient deficiency, it is key to talk with your healthcare provider to complete a full assessment and get recommendations on correcting it. Sometimes, diet and lifestyle modifications are enough to reverse nutrient deficiencies before they become severe, and other times, supplementation is needed to help improve these levels. Talk with a dietitian to learn more about consuming a nourishing diet to promote optimal digestive health in advanced age.

1. _{Cristina, N. M., & Lucia, D. (2021). Nutrition and Healthy Aging: Prevention and Treatment of Gastrointestinal Diseases. Nutrients, 13(12), 4337. https://doi.org/10.3390/nu13124337}

2. _{Panda, A., & Booth, S. L. (2022). Nutritional Aspects of Healthy Aging. The Medical clinics of North America, 106(5), 853–863. https://doi.org/10.1016/j.mcna.2022.04.008}